Sell domains in site like wordpress.com

Hi all,
Just wondering if anyone has set up selling/ registering domains like wordpress.com, as I feel it would be a pretty good value added service.
I found this plugin http://www.zingiri.net/plugins-and-addons/remote-provisioning/
which I allows you to hook in to the WHMCS billing system (I think :s)
If this can be done, is there an easy way to add the purchased domain into the domain mapping plugin.
Cheers,
D