Luckily, I had a fallback plan.
At this particular urban center, business-class cable was available from a local provider. For around a couple hundred bucks a month, I could terminate a 2Mbit up x 16 Mbit down business class cable modem circuit. By bonding multiple 2x16 links together with any number of low cost solutions out there, you can easily get a crazy amount of the bandwidth for a much cheaper price.
Now, I'm not advocating that you ditch your Internet T's or DSx circuits for business class cable/DSL based solely on cost, but you don't need to pick one option over the other, that's the great thing about Link aggregation. If you already have an internet T from a Tier-1, and you need to add bandwidth, why not multiplex in a cable link through a WAN Aggregation appliance? For relatively cheap dollars, you can buy an aggregation appliance from Elfiq, Radware, XRoads Networks or Fatpipe to perform the bonding. Some of these appliances also come with some slick routing and QoS features as well that potentially offer solutions to other business problems that may have.
Another benefit of WAN Link Agg. is carrier diversity and automated failover. If you're managing a highly available environment, do you really need to pay top dollar for that carrier diversity? I'm always on the hunt for new and interesting products in this space, so if you've come across one that I haven't mentioned and you've had success with it, shoot me a note. And if you have a Link Agg. horror story to share, I want to hear about that, too.