have you considered dialing two lines (two modems) and tying them together? Windows 2k and newer can do this. I haven't tried it, but it should work fine. FWIW, 128k DSL does something similar (2 B channels at 64k each, albiet with a digital line).
The only issue is whether or not your ISP will allow you to log in twice.
Chris
Back in the pre-dsl days I used multilink-PPP to hijack the familiy's voice phone line at night to increase my download speeds. It works, and usually can achieve speeds up to 80-90kbps. Better than nothing, but still dismal these days. The ISP does need to allow it, back in 1998 mine did by default, I have no idea if this is the norm these days.
You're referring to IDSL which is SDSL running over an ISDN line. This runs at 144kbps and can reach out to further distances than normal ADSL that most companies offer. It's more expensive, though, and still rather slow.
The satellite providers come in at the 256-512 kbps range, which is a usable internet connection, but they have other issues, mainly very high latencey and tricky Fair Use Policies which can slow the connection down to a crawl if they deem you've used too much bandwidth.
For reference, most DSL and cable modem service these days is running 1500-3000kbps down. Much faster than any of the other options.
Another option that most people aren't aware of in some ares is fixed wireless service. Many small companies are rolling out this service, usually in flat, rural areas. The service is a wireless radio connection to a land-based radio tower in the area. Speeds and quality of service can vary with the provider, some of the guys doing this are one-man operations. But it isn't as affected by weather as satellite is and it doesn't have the 500ms+ ping times. Something to look into if it's available. Google for WISP or Fixed Wireless.
