Beam antenna on the roof? If you have a line of sight, a decent yagi antenna mounted on a roof antenna mount (the kind Radio Shack sells for tv antennas) and a couple hours of work on a Saturday and you can have Verizon's 4G/WiMax data rates, which although not cheap, would offer a fine alternative path for a multi-homed setup. Won't be attractive, though. Wife might object.
Sadly, they do not have WiMax in range of any height of antenna I could have access to on my property. They have FiOS, their new fiber optic setup here in FL. Its fuggin sweet too, 50Meg+ and caries T.V. cable, and regular phone of course over it as well. Too bad I am way out of range of it. ;p Only WiFi capable towers here are 3G ATT/Sprint, and a local company that is selling the same tech that I was 10 years ago, for about 3 times the price of what I was well profitable at. ;p Probably same situation as my current biz and lack of upstream choices. If I was him, I'd move my bis. In my situation and the non public nature of my hosting it would not benefit me, like it would him.....
Yea, before I moved the previous ISP I owned had a dual band 4.8GHZ(2.4-5Ghz at 19.3 to ~22db) LNA setup that I could line of sight to my customers and of course to my home that was nearly 5 miles out. It took a friggin 6 grand dual-pole transceiver antenna(God those things have gotten so much cheaper) up a 45' poll at the time to do so.
Now, I could LoS from my closer biz to my house with about 12 grand worth of equip now and have access there but the speed would not be any better than what I have now and god only knows what the new licensing on the channels is these days. I know it has changed a LOT since FCC whacked out a huge swath of bands from what was pretty much open use previously.
Cheers