Flexibility in rough-in dimension?

We were having a new low-flow toilet installed in our fifty- year old house and discovered when we pulled the old toilet that the rough in dimension is 9.75 inches. I can find a few toilets with a 10 inch rough-in. I am not finding anything with a 9.75 rough in. Is there some kind of device or technique which will make it possible to install a 10-inch rough-in into a 9.75 area? Please help, and thanks.

Many (not all) toilets have a space behind them when installed on the specified rough-in dimmension. So, yes, some 10" rough-in toilets will fit, some won't. Most of the Toto's that use the Unifit adapter (Carlyle, Vespin, and a few others) have a nominal 3/4" behind them, so, you'd still have 1/2". You need to read the spec sheet carefully.

Note, the rough-in is measured from the center of the drain to the finished wall (not the baseboard unless it is extremely tall). Did you measure correctly?