Fred, Currently I have comcast into my basement and then to my LR. There I have cable modem, router with wifi, tivo. I don't have wired ethernet to anyplace else. Wifi is bad in a number of places away from the router. (This is in a relatively small condo - ~1600 sqft.) My primary goals are to improve wifi throughout, and allow for a tv on a tivo mini upstairs. And secondarily to provide hard wired network access in some key places upstairs and down. (No particular needs for that other than to provide a faster path when doing something intensive.) The key constraint for me is getting wires to the right places, especially from downstairs to upstairs. I recently had some other work done that required pulling thermostat wire upstairs. A place to do that was found next to the main hvac return plenum. I had the installer drill holes extra large and leave me a pull string when doing that. But the holes are still only about an inch. So I am limited in what I can get between floors that way. Hence my intent to pull a single cable and use a switch upstairs. (I will probably pull an RG6 along with the Cat6, just in case it is needed in the future, but I don't have a current need for it.) My intent is to hang the wifi access point on the wall of the stairway from 1st to 2nd floor. It is quite central, and I can wire it through the wall from that upstairs closet. Given the size of my condo, I hope that will give me good coverage in all living spaces, and it won't look ugly. And I can get to that closet from the attic, after running from the basement up there. I will move router to basement (turning off its wifi) along with the cable modem, with a CatN from it to the tivo in the LR. I realize that the the result will only be as good as the worst link. I figure that will be good enough for now - it should still be a significant improvement over my current situation. And I can upgrade other components later if needed. I guess the key question is how good a switch to get, since I don't currently have one. I'm not going to pay $1k. By the time I *need* more than 1gig I can hope that the prices are down. I don't need the switch to hook up the access point. Only when I want to also connect to a tivo mini and to other wired drops upstairs.

I'm afraid that cut-out wall would forever bother me. Could the holes be filled in and the wall continued toward the other wall on the right, so that there is still a pathway on the left? If not load-bearing, why not remove it, and I think someone mentioned putting a wooden beam in the opening, which would certainly add architectural interest.

This will sound complicated, but it's not really. I'm just being very specific. This method is safe, as long as you follow the instructions carefully. Buy a non-contact voltage tester at the hardware store. If you don't have a simple neon test light, buy one of those too. Buy a polarized extension cord. (All cords are, or should be, polarized these days.) If you don't have any extra #18 or so stranded wire lying around your workshop, get several feet of that too. Back home, open the breaker to the circuit. Remove the luminaire (light fixture) and leave the wires from the box exposed and extended, well-separated. Turn on the breaker and the switch controlling the light. Touch one wire of your neon test light to the box (if the box is metal) or the bare ground wires in the box (if box is plastic), and the other to the black wire. Your neon tester should light. Now move the tester from the black wire to the white. It should NOT light. If the tester behaves other than above, your circuit is miswired. STOP -- DO NOT CONTINUE WITH THE FOLLOWING STEPS. Otherwise, open the breaker to the circuit. Open the breaker to the circuit. Open the breaker to the circuit. Make absolutely sure the circuit is dead. Test the wires from the ceiling again with your neon test light or voltmeter, to be absolutely sure the circuit is dead. Do not skip any of the above steps. Find a nearby receptacle on another (live) circuit. Make sure your cord is long enough to reach from that receptacle to the ceiling light you want to modify; add another POLARIZED extension cord if necessary. Cut off the receptacle end of the extension cord (unplugged of course). Separate (or strip off the jacket if it's round) and strip the individual wires. If the wires are the same color, put a piece of black tape on the one that is smooth, not ribbed. Carefully tape the stripped ends to a nonconductive counter, workbench, or table top, so that only insulation is touching the surface, but the bare ends stick up an inch or two above the surface. Make sure the bare ends have at least 3" of open air between them. Making sure there are no kids or pets around, carefully plug in the cord and any extensions, using the receptacle you found above. Avoid touching the bare wire ends. Touch or connect one wire of the neon tester to a known-good ground. This can be a water pipe, or the METAL center screw of a receptacle cover, or the ground pin of a receptacle. You will probably need an extra length of wire. Touch the other wire of the neon tester to each wire of the cord in turn. It should light when you touch the SMOOTH (black-taped) or black wire of the extension cord. It should NOT light when you touch the RIBBED or white wire of the cord. If the light doesn't behave as described above, either the receptacle or the cord is miswired. UNPLUG THE CORD AND STOP -- DO NOT CONTINUE WITH THE FOLLOWING STEPS. Otherwise, unplug the cord and untape it from the testing surface. Connect the stripped RIBBED or white wire of your cord to the white wire from the ceiling box. Connect the SMOOTH (black-taped) or black wire to the black wire from the ceiling box. If you reverse these connections, you'll get a nasty arc when you plug in the cord, and will trip a breaker, so be sure you get this right. Plug in your cord to the SAME RECEPTACLE you used for the test above. Hold your tester next to the cables. You may have to physically separate them by several inches. The one that makes it buzz is the one you want. Mark it. Unplug the modified extension cord and disconnect it from the ceiling wires. To prevent accidents, discard the cord, or at least cut off the stripped ends and tape them.

My guess is that if your roof is framed with trusses that adding additional attic space would be very challenging at a later date. The same goes for if the media room is in any way changing the roofline. Chances are in any case that if the cost to build it is 14k now, you will spend a lot more in both cash and headache to go back and do it later. To the point that's it's not likely to happen, so I would go into this thinking you are making your final decision now. If you wanted to save some dollars now though, you might ask the builder if it's possible to build this more like a bonus room with all required framing, window, door, and stubbed in electrical without doing any finishes. You might be worth few thousand, but still expect to pay more than that when you get around to finishing. The nice thing about this particular media room for resale value is that you could sell the house as a 5 bedroom in the future.