Unless you can hide the cut edges it is not going to look as nice as factory molded edges.

We are talking about natural marble, right? I must respectfully disagree with brickeyee (which is rarely a good idea). It sounds like he is speaking of ceramic tiles ("molded edges"). If you cut the marble tiles on a decent diamond saw, the edges will look the same as the factory edges.

I cut all of my 6x6 travertine tiles from larger 12x12 ones. I could not tell which edges were mine and which were factory.

Here is the saga of my decision to go with 6x6, which includes some cutting info:

http://ths.gardenweb.com/forums/load/kitchbath/msg121903224045.html?13

and here are some pictures of the final product (grouted and, below, ungrouted, so you can see the edges better):
http://ths.gardenweb.com/forums/load/kitchbath/msg021817271392.html?1

And yes, it is real marble. And my husband did say he'd need a special kind of wet saw, I guess that's it. You're backsplash is beautiful! Thanks for the links!

One question, were your edges straight? We looked at the marble yesterday and there is a slight ease to the edge, not sure if that would show up after grouting. It is a third of the cost of the alternative so it's tempting not to try.

"If you cut the marble tiles on a decent diamond saw, the edges will look the same as the factory edges. "

This is correct.

If this is stone the edge can be made clean and usable.

Yes, my edges were straight, not eased.

Unless the ease is really big, like a small bevel, I doubt it would show up.

You could ease the edges yourself using an abrasive stone. (They sell them for this purpose, mostly for getting rid of the really sharp edge on ceramic tile.)

Another option is to make three cuts per tile. Instead of trying to cut the tile exactly in half, you could make the final tiles, say, 11.5". First you cut all the tiles in half. To do this, you would set the fence on your saw so that the blade came close to bisecting the tile. Then you set the fence a little closer so that you can cut a little sliver from the tile. Turn the tile around so that you are cutting off the eased edge.
This would have one advantage and one disadvantage. It is actually a little easier to get the tiles all the same size this way, rather than having to exactly bisect the full tile. The disadvantage is that I am a bit worried about keeping the tiles exactly parallel. 24" is a big rip. Not all saws can handle it. You have to be careful that your cuts are truly (and consistently) perpendicular to the tile edges.

A third the price? Go for it!

Thanks so much for both your replies!! I am going to print this out for my husband. And and it's a third of the price and I like it better, so we will!!