osmocom with USRP1 as a sw-only MS?

Hi all, after some days digging into the various tools around the GSM opensource playground arena i started understanding better the various piece of software. It seems to me that there's a net separation between the GSM implementation stack of OpenBTS and Osmocom, also because the projects are born with different goals. With the current bb implementation of Osmocom inside Calypso based baseband processor of motorola, all the DSP logic is done directly by the mobile phones chip, right? Which with OpenBTS, it's OpenBTS itself that does the modulation/demodulation along with the USRP. Is there some project and or ideas to bring together the DSP codebase of OpenBTS, together with OsmocomBB to make a MS terminal based on USRP1 device with RFX900 boards? Fabio