Most likely there will be a separate phone for CDMA. Keeping costs down is important, especially since I believe that, at the same price point, the average consumer will have a hard time choosing a product over the iPhone.
In the long run google will probably be competing on something other than price, I'd expect them to roll out a whole pile of android specific service improvements.
Qualcomm's GOBI platform seems to support basically everything but is currently only available as a miniPCI card: http://www.gobianywhere.com/files/gobi2000_overview.pdf
<speculation>Maybe Apple's tablet will have one of these.</speculation>