New details are emerging about a new Treo on deck for Sprint, the 800w. The full-sized, Windows Mobile-powered smartphone is said to be in the beta stage, with Sprint rumored to have sent an email to select business customers who use WiFi and Bluetooth in a pitch for testers.

This means that this device would be the first Treo with WiFi built-in. So far, Palm’s kept WiFi at arm’s length with its smartphones, opting instead for more wireless options like EV-DO and EDGE.

This is notable because the main complaint T-Mobile has with Palm, and according to sources why T-Mobile doesn’t sell Treos, is the lack of WiFi. If it becomes a standard feature, and it likely will, we could see Treos hitting T-Mobile soon.