Private Mobile Network & GSM Transceiver Design

Hello everyone, I want to make a private mobile network using my own transceiver. It is easy to implement using Universal Software Radio Peripheral Kit USRP1, Asterisk PBX and OpenBTS. What I want to do is that replace USRP with a transceiver and use it with OpenBTS to make a network. Transceiver would talk to a mobile handset by showing an Air Interface. I'm unable to find helping material for doing this task. GSM Transceiver chips and similar data is available but my main task is to make a transceiver with the functionality of USRP1. Any help would be appreciated.

All right. You want to compete with AT&T, with Vodafone, or other carrier providers.
Don't forget before going on the air, you have to buy license for using particular frequencies. Sometimes they cost millions of dollars.

How about Astrix PBX + WiFi + WiFi enabled smartphone with SIP client