For the cost of one of those T1 lines, you ought to be able to hook up about four (or more) of the DSL lines. Figure 3mb/s each, that's 12mb/sec -- quite an improvement over the T1 they replace, and you've still got the other (reliable) T1 there too.
Excellent idea, but I neglected to mention that I wasn't even getting 3Mbps when the guy set it for that speed. The performance was terrible. It was getting around 300Kbps down and 70Kbps up. That was with my laptop plugged right into the modem they supplied. Even worse, the connection kept dropping. I could stare at the link light on the modem for a minute and watch it go out several times.