not many people stick with one equipment manufactuerer anymore. There are plenty of 15's that would do the trick for your power range though,...ones that come to mind are the Massive Audio DMX (quad 1 ohm sub that is 3000 RMS and 6000 max), the Ciare SPL 4000 (3000 RMS quad 1), American Bass VFL, RE MT, TC Sounds 5200, Digital Designs 9515.
If you're going for the unlimited budget, why screw around with anything RF has to offer //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif