YES YES YES! This is MUST-HAVE feature. If we're running a promotion, we should be able to properly reward our affiliates for driving not just signups that result from their direct link, but from all child signups that result from their direct referrals.
I think this could be fairly easy to do with embedded promotions on our own sites - just allow the initial signup to capture the affiliate ID from the URL parameter, and then subsequent UV links append the proper affiliate parameter string with that affiliate ID to the link.
Please reply to let us know if you're working on this, and when it might be available.
I've been trying to do workaround for this and I can get it working but it's ugly. I'm hoping you guys can add this as a native function.