Your setup looks sweet, and you can use hook_form_alter() to add anything to that form. And you're totally a bug finder now.

The feature to incrementally add recursive products to users is ripe for core inclusion. I don't know if Shawn had a chance to address it or not. I'm totally stoked about getting Shawn's last two modules in core, though. These were the 2 most requested features on the forums and at Drupalcon.