Kevin...
If I were you, I would also do two packages for IBers.
1. For those that have money to spend, Four Tempest-X's, one woofer widget and an FS1200TS (325 watts to each speaker given each sub is 4 Ohms and they are wired in series). Since most IBers have their drivers all co-located, only one widget is necessary. An 8 Ohm load is nice and easy... decreases wear on the amp and likely keeps it quieter. 325 watts to each speaker should also be just enough to get them close to excursion limits without going too far (plus you have the woofer widget for added protection)
2. For those with a bit of a budget, Two XJ-18's, one woofer widget and one FS500TS (500 watts each provided the subs are 4 Ohms each). In this case the woofer widget would pretty much be a must for protection.
I would also ask ThomasW at The Cult of the Infinitely Baffled if you can post your prices there. If so, I think you'd get a lot of sales. I would also mention that it can be coupled with a BFD if people want more PEQ channels as well as your 30 day money back guarantee on fan noise.