Robert-W, I did just that about 6 weeks ago on our 2004 Allegro. The front Michelin XRV tires were badly cracked on the sidewalls. The rear tires on the outside were not cracked nearly as bad, and the inside duals showed no signs of cracking. I had the rear duals switched side to side, and outside to inside, and replaced the fronts with new Michelin XZE's. The tires I replaced were the original ones and and were 5 years old. I plan on running the crossed and rotated rears another 2 years. Hopefully!
Not nearly as bad on the old wallet this way also.