WHMCS is owned by Matt, however, the chief software architect for IPS/IPB is also a Matt (Matt Mecham). IPS is launching a modular product that competes with WHMCS, so I don't know how willing they would be to help integrate this product into their forum software.
Yep, the IPS product is called Nexus.
The problem is, Nexas is in beta, and I don't think it will be anywhere near as good as what I've seen from WHMCS, in regards to it's interfaces with a wide range of payment gateways, domain registrar's and server systems..
So I wanted to go with WHMCS..
I guess I'll try the Nexus beta out soon..
Ta for the reply, uberhost!