Upload & Sell: Off
Sacramento isn't exactly a hub for photographic equipment sales and rentals. Pardees in Carmichael rents whatever they have in their used inventory, but that's rarely anything exciting. If you desperately need a T90 for a shoot, they're your best bet, but 300-400 in EOS mount, forget it! It's possible they have a 2x Teleconverter in stock if you can get your hands on a 70-200.
I live in Folsom and don't think they're worth the 20 minute drive there (mostly because of their customer service and prices) but if I need something that's going to set me back some serious coin, I go online.
I think your best bet for rental is with Calumet in San Fran, like maxx9photo says. Your second stop might be with Adorama or someone who will ship a rental to you overnight. Last option would be to pick up a 2x teleconverter and put it on a 70-200 if you can live with it turning into f5.6 instead of 2.8.