Simon,
Great news :)
While I have been working on something simular, it hasn't been with OpenACS (only AOLserver). I've had a customer ask me to modify the uptime software use paging services (qpage) so they could they can use uptime for text paging noificiation (and as a general paging server).
My approach was going to be just creating some TCL wrappers around a stock qpage installation. If you have developed modules already it might be worth while to look (once they are released, hint..hint..)
Congrats!
