There's lot's of places who rent them in Arizona and Baja Mex., for those with a real sense of adventure... you'd have to take their tours though.
The Vstrom would be good for paved roads with patches, the XR650L good if you just need to hop on a road for a few feet to get to to the next trail... actually it's not bad on the highway, but I used it primarilly as a trail bike. The Kaw KLR650's are a great in-between choice, and there are tons of touring accessories available for them. They have quite a cult following.
By the way, I'm a new guy... my name's Casey Fry, Scott knows me. I recently bought a house in Leander, and currently ride a Honda NX650. I have an interest in all forms of riding, but am cursed with a particular passion for off-road and adventure touring. I've been on a 1-1/2 year hiatus from riding, a result of a nasty injury to my right wrist. Yep, the wrist that makes it all go. I'm on the road again, looking forward to what's to come.