I want to buy a RIM 5790. What service provider options do I have besides Singular at $40/month or RIM at $44/mo. Where can I purchase the 5790 besides RIM?

This device operates on Mobitex networks. This technology is limited to about 8kbps. Compare that to the latest EVDO Blackberries at 400-700kbps.

I believe Cingular is the only Mobitex carrier in the U.S. So your options are limited...

Cingular sold the Mobitex network a few years ago to Velocita Wireless. They sell the 5790 also. Check for them here - http://www.velocitawireless.com/