Wow! Many thanks to all for your responses. Unfortunately, there is piping in the wall in back of the toilet that won't allow for a wall-mounted toilet (which would have been the perfect solution). I just posted at Terry Love (thanks for the suggestion!) and someone referred me to Nameeks - and I'm exploring that possibility (it's expensive and also would require a 36" tall tank - but with a round toilet, I'd end up with a 23 1/2" total depth, which would be great). Not sure that Nameeks will work, so if you have any other thoughts, please chime in! (And I'll let you know if I find anything else out from the Terry Love site). Many thanks.

American Standard is the toilet that I most often sell for those cursed with a 10" rough in. It has a good MAP rating and is decent looking. I'm not at work right now to look up the particular models that are available with the 10", but there are only a couple. Most often though, I recommend that the waste pipe be relocated to be able to use a standard 12" rough in so that the choices are not so limited and better flushing performance can be achieved. Even if the slab has to be broken, it's often worth the investment of the upgrade.

I believe Toto has a number of toilets that fit your requirements. Check out, for instance, the Soiree. Here is a link that might be useful: PDF of Toto Soiree

problem solved ! A friend dropped in who had the same problem in the past. We picked up a couple of 3 inch abs 45 degree elbows and a 90, along with a new coupling. We attached one 45 directly to the coupling and the second 45 directly to the first, creating a 90 with a "gentler curve", which reportedly prevents clogging, We hen attached the 90 at right angles to the two 45's to accept the toilet flange. The result placed the center of the flange 12.5 inches from the wall ( acceptable ) and only 2 inches to the right of the old midline, thus not crowding the vanity on that side. Excellent,!! How come I hadn't thought of that ?