Monona PD already went to 800. Trust me on this ;-) They have the equipment, but I do not know for sure if it's to replace the VHF dispatch they have now or use the 800 for mutial aid reasons.
There is talk about Dane County joining in with the City of Madison's TRS system. However, the last rumor I heard, is that the Sheriff's office will go to 800 but the fire/ems will stay VHF (for mutal aid reasons).
However, no firm confirmation on this. They City's 800 system is more then able to handle a countywide expansion. I guess the county would just pay for it's expansion on their end.
Matt