Yes and no. Mobilecasting is one of those activities that can cost as much or as little as you'd like. For the very few times that I've actually recorded something on the road, I've used my iRiver T10. It's small and adequate for recording very clear stuff in areas with little backround noise.
Sadly, there isn't a lot of interesting stuff occurring clearly in areas with little background noise.
I think it's likely that only podcasters intending to do a decent amount of mobilecasting would be likely to spend enough money on the variety of gear required to cover all mobilecasting possibilities. Long sentence, eh?