The trick in those specs you are looking for is finding ine that will shoot raw. There are only a (ever decreasing) handfull of compact cameras that will do it - I assume you're looking for a compact based on your price range.
Firing a strobe is very easy with most modern strobes since they can optically slave off the camera's intenral flash. If you want a hardwired connection, then you'll need to find a camera with a hotshoe and a housing that supports it.
Most of the newer canon's can use a "hack" to let them shoot raw. If you are willing to use optically triggered strobes, and use the "hack", one of the most popular cameras on the board right now is the canon 570is with the canon housing. Up until recently the set (camera+housing) could be had for about $300, but it seems they are getting scarce.
If not, right now you're best bet is probably a Cannon G9 with the ikelite housing, but you'll end up going a bit over your budget.
Of previous generation cameras, all the talk was about the olympus sp350 - complete set of shooting modes (manual, auto, aperture & shutter priority), hothsoe + raw capability. You'd have to dig a bit to find one (you'll probably only find used or refrubished ones), but if you do, it should come in well under budget.
