SCC used for WAN connection

Hi,

I'd like to use one of the currently unused SCC's as WAN interface.
My ultimate dream is to run PPP or Frame Relay at a speed of 2Mb/s on it.

Is someone out there, who has
1. seen something like this?
2. written some kernel modules which support this functionality?
3. seen links containing related information?
4. ideas on how to do this?

If you were doin' something like that, would you first buy a WAN Interface
card for the PC? (eg. Sangoma, for tests?)
5. Has someone done tests with such a WAN card?

Thanx for any information,

Ruedi