It certainly could be done, but falls so far from the practical as to not be worth it. You're certainly not going to stop driving, yank a pin, round the corner, and re-pin it...
FWIW- I think you're best to examine your priorities and build based on them. If you want the best traction possible, use a traditional live axle. If you're operating on asphalt or concrete exclusively and are much more concerned about road manners and maximum tire life, then only drive one wheel or install a differential, such as a Tecumseh-Peerless 100.
If you have access to a machine shop and some high-dollar tools, there is an option you could explore that will do the same think as your pin concept but MUCH slicker-
From the agricultural tractor world- Picture a live axle, but cut off centre. One side is driven, full time. The inboard ends of the axleshafts are splined, with a similarly splined collar that can slide on those splines. A pedal (or lever) operates the collar. The collar would slide over both splined axle ends to lock the shafts together for full traction. For cornering (or whatever), that collar would slide right off one axleshaft, and rest only on the other shaft. See what I mean?
