You're right - that isn't much to go on! With perhaps 500 named cultivars in commercial trade and many fitting roughly that description, not to mention a few dozen more cultivars of shirasawanum and japonicum that most folks think are also J. maples, any guesses would just be a shot in the dark.

Fortunately the Puget Sound area of Washington state is home to dozens of excellent nurseries, many featuring large selections of Japanese and other Asian maples. A number of public gardens and arboreta also have maple collections you can view for comparison. We have just peaked with fall color on most maples in this area and they are starting to drop leaves, so now is perhaps not the optimum time to select based just on fall color.

One cultivar you may want to pursue is 'Osakazuki', which is known for stunning fall color. Pretty popular in this area, it will develop a rather horizontal branching pattern and is often sold multi-trunked or with a very low crotch. It will get quite a bit larger than 12-15' in time, ten years being rather young as J. maples go.