Not to mention you're already running a VoIP client (of sorts) full time on maemo. Have people forgotten that you can do voice chat with your Google Talk contacts (and even video chat, if they're on a Nokia tablet as well)? With the rtcomm beta it also supports SIP for VoIP calls, and has a phone dialer. VoIP is definitely a viable alternative to traditional cell phone radios, assuming you can get an internet connection wherever you want.