I found out that N810 is able to offer mobile skype for me. My BT handsfree is paired to N810, which is coonected to internet by BT enabled 3G phone. This combination offered me total mobile skype, while driving around Helsinki. Voice quality was ok, even 3G handover was couple of times problematic. But staying still, phone locked to 3G network - everything worked.
I think this might be one of the reasons why Maemo does not hit phones real soon, too much superior functionality which breaks barriers of current carriers.