How can I find a toilet which stubs out 11 inches from wall? Is this a special order?

If the center of the rough toilet opening is 11" from finish wall a regular 12" rough toilet should work, the tank will just be a inch closer to the wall. They also make 10" & 14" rough in toilets that are not special order if you are dealing with a plumbing supply house.

I agreev with Puff. It will be tight but *I'd try installing the toilet.
Make sure the bowl's pulled as far forward on the flange as possible. Good luck, Tom

Offset closet flange would do the trick, as well.

I don't like to use a offset flange unless I'm forced into it. Try the 12" toilet. Good luck, Tom