At least this is new to me. Last night I saw this from another website and I called Disney today and it is true:

Effective Nov. 1, 2012, WDW will implement a new ECV rental policy. DIsney has selected 5 scooter/wheelchair/ECV rental companies as approved vendors. This means these companies are the ONLY companies allowed to drop off rentals at the front desk/bell stand ofa Disney resort for them to be held for guests. Guests using these companies will also be allowed to return their rentals to their resort's front desk when they check out. Vendors that are not on the approved list will now have to arrange specific meeting times with their customers and deliver the rental in person. Likewise, when the rental is completed, the guest must make arrangements to deliver the scooter to the company. Disney will no longer provide a courtesy hold/storage for vendors not on the approved list.

I called Disney this morning and here is the approved vendor list:
Apple Scooter
Best Price Mobility
Buena Vista Scooters
Care Medical Equipment
Scooter Bug

Thank goodness I'm using Apple for our trip in Jan.