You give no figure for how many pixels are required...
At the end of the day, you might be better off looking at something like the Starlight MX916, and writing a driver yourselves (some people have done individual Linux drivers for the Starlight cameras). The new USB 2 interface (due out over the next few weeks), offers about 1.5sec loads (at full resolution), but even the existing interface will get close to your required speed at 2*2 binning (at this you get about 17um 'pixels', just below your requirement).
Alternatively, the SBIG ST7XEI, was selling well under your required price (the 7XE, with a seperate guide CCD, is only about $2700, and the industrial unit without this second chip, is normally about $700 less). This has 18um pixels when binned 2*2, and peak sensitivity at about 540nm.
Unless you need the low light performance, and colling of an astronomical camera, you will get a far cheaper device, by simply buying the industrial version of a standard camera. Hitachi offer a number of IEEE1394 industrial cameras, with the smaller units, falling inside your price bracket, as do a number of other companies (Sony, and Dalstar for example). These sometimes appear in auctions for really reasonable prices.

Best Wishes