I have some experience with the Vifa sub (299-229) that someone posted. This is a nice speaker but it needs a fairly big box (2.5+ cuft) to work decently.
Have you considered looking at a premium 8" instead of a 10" speaker. An 8" in a properly sized box is going to work as well or better than a 10" in an undersized enclosure.
Look at some of the higher end Phoenix Gold stuff, although I don't know if any of these might meet you mounting depth requirements.
