I did something similar to what you said, I just instead named the pack so that the slug would be the same, but didn't link it until after I created it.
I'd like to try to make something like this, may take me a while to recode portions to add some more permissions:P
Seems like solder has had plans for it as there is a field in the mysql database called modpacks under the solder_user_permissions table
I'm having issues creating a modpack on http://technicpack.net with selecting import from solder. What happens is it goes to an empty page when I click create modpack. Anyone else having this issue?
Ok added some images:
Images seemed to big, so I will just give links
http://imgur.com/EWaX40L,qsGJoI2