Yeah, takes all of about 2 minutes if you know what you're doing (where's the emoticon for sarcastic eye rolling?)
But I agree that true mudders are generally terrible on mixed terrain.
Two wheelsets ain't a bad tip except my wheelsets run over $600 (before cassette & tires). Eeek...
IMO the two wheelset is the way to go for a number of reasons. Esp if you own more than one bike. Hey Phil.....!
Actually, very good wheelsets can be had thru Colorado Cyclist, Performance and Nashbar for under $300. Standard 3 cross.