Approve new users?

Anybody know of a plugin that lets sub site admins approve users who come over from the main blog?
I tried Membership plugin but it didn't work with disabling a marketpress shopping cart (which I need) so now I am considering disabling access to the entire subsite blog until a user is approved by the sub site blog admin.

I tried New User Approve Plugin but it is not set up for multisite.
I am trying to avoid having members fill out a new registration form each time they apply to a sub site.
Suggestions?

Thanks.