Wirelessly posted (BlackBerry8700/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/100)

Why not just rent the car specifying a return at the same location, then call in the middle of your trip and change it to a one-way?

This will be pricey, no doubt, but I doubt Avis would deny a change like this if you tell them you're unable to return at the same rental location.

I used this tactic with National one time from MDW to MKE. MDW had plenty of cars but told me "no one ways," so I called National after driving off the lot and changed the return location. Cost me $75 extra.

Never done this with Avis, so YMMV however.