The WiFi version takes the same amount of time to charge up. And the 4G chip doesn't seem to drain the battery that much faster than WiFi anyway. (9 hours vs 10 hours)
And the iPad does come with MiFi capabilities... if your carrier supports it. Verizon in the US does, and you an connect up to 5 devices using the ipad's 4G signal.
Did you really have to bump a 2 1/2 month old thread.....?