It really is ideal to leave 3' between the house and your shrubs. Try to picture as the new shrubs get larger you will have no space against your house at all. Consider making your foundation bed deeper and move the yews farther out so that you can put the upright shrubs against the house and still leave 3 to 4' for air flow and maintenance access for your house. No shrub wants to be jammed up against the wall of house with no circulation. I think the cannas you had there were flopping over because they were reaching out for more sun(they were too close to the wall). Also most houses have a roof overhang that keeps the area right next to the house dry-- too dry for most plants. That all being said some columnar plants... Juniper "sky pencil" or "Blue Arrow" (to 12') Buxus " Green Tower" (to 9' tall) Barberry "Helmond Pillar" (burgundy foliage-only to 5') Rhamnus "fine Line" (to 6'- not evergreen but a nice Lacey contrast to the yew) Good luck!

Without a photo I am having a difficult time understanding why privacy is needed at the front end of your driveway which presumably leads to the public street? One would think privacy activities take place in the back yard. That said it is your right to want it :) But eighteen inches of width and a desired height of eight feet that behaves and stays that size is a tall order- it would be my opinion that anything you do is going to require more maintenance than it is worth unless pruning is your favorite hobby. I don't think DeGroot's would be good for privacy as they are so narrow toward the top. I have three in a group and while they are one of the best looking arborvitaes I have their use is more architectural than screening. Mine have gone from a couple of feet to approximately six/seven feet in five years. How long are you willing to wait? And I have to say that the thought of pruning a plant as naturally perfect in form as a DeGroot's makes me a little ill. Again, without a photo it is difficult to say but I would plant something thick and screening down as far as was practical and then use decorative boulders in the narrowest section. Or surprise my wonderful neighbor with some plants that he could plant on his side of the fence. Maybe a neighborly discussion is in order?

Degroots Spire evergreens can make a nice thick and narrow hedge of trees. They also can be used alone as accent trees or to soften the look of hard lines or corners often found in buildings. They are expensive, but will be well worth the investment if you purchase ones that are 5-6 feet tall, B&B ones that have been potted in 25 gallon containers, while being left in their burlap. Ask your nursery man how far to space them for the screening affect your desire. If the soil where you want to plant them drains fairly quickly then make certain to keep them watered when the rainy season is over. Do this summer and winter at least for the first three years after planting, and there after if you see any of their inner, or even worse, lower leaves turning brown. They probably would suffer too much of planted in soil that stays saturated for long periods of time.

I think you're out of luck. Any clumpers that would survive your climate (same as mine pretty much) would not be very upright, and would take probably 5 years to reach the height you want. How about running bamboo in large pots? Might be worth a try, although I'd be most concerned about winter damage.