Personally, I have recently calculated the approx. cost (not including little odds and sods) to built a Baja buggy with enough reliability, runtime, and power... the cost came to over $3000. This is using such components as a Neu 2230, a decently sized A123 pack that would have at least 7000watts capability, i can't remember which controller I priced in, but expensive none-the-less.
In time, I might attempt one of these... and when I have more 'surplus' budget.
It would be a sight for sure!