I'm working on a Live chat module for WHMCS that is turning out pretty well
The best combo right now would be
WHMCS + Livezilla
Blesta + Livezilla
Clientexec + Livezilla
If your billing system does not handle support tickets, I would suggest Kayako.
We have Kayako, but decided to use Livezilla. Livezilla is great being a free software! No issues what so ever with Livezilla its also very easy to setup. Kayako we had a lot of problems and the support at Kayako is slow and it sometime feels like Kayako doesn't care.
Do keep us updated, I'd be happy to give it a test run and review when a beta is ready
Do keep us updated, I'd be happy to give it a test run and review when a beta is ready