Been done (Score 1)

I work for Nortel Networks. We have been partnering with Symbol to do this for over a year. The Symbol phones(http://www.symbol.com/products/wireless/nv_ phone.html)use H.323 and work with our Succession IP telephony systems(http://www.nortelnetworks.com/products/01/ succession/es/succession_cse.html). Of course it doesn't count 'til Cisco does it.