I could have sworn that the owner's manual says it's OK to drive limited distances with the rear drive shaft removed. I think it was in context of flat towing a 4wd Ranger behind a camper (with the rear driveshaft removed) and Ford approving this for driving around the campsite or to the store on the front driveline alone.
Honestly, I don't see how this would be a bad idea. I mean, I might question the front axle's strength for doing smokey burnouts or turn-the-wheel-and-floor-it manuvers. The front end has to be strong enough to hold up to a stock truck up to GVW, so why can't an unloaded truck handle itself with only the front end?
Just throwing that out there...
1999 Ranger 4.0 Sport --SOLD!--
2009 F250 XLT CrewCab ShortBed
5.4L / 6 Speed / 4.10LS