I could be way off, but I think a supercharger setup could easily end up running you close to $7k+. A full V8 swap, depending on if you find used, and if you do the swap yourself or not, could also range anywhere from $5k to as much as $20k+ if you go crazy and get a brand new crate w/tranny. For reference, a brand new LS3 crate with automatic trans is like $17k.
I know what you're looking to do has been done, but I certainly don't have the details or specs to be of much help.... I know I tried to look at SC kits for this engine years ago and was disappointed that the entry point seemed to be about $7k.
Honestly, I think your best bet is a full V8 swap if you find something good used. It *could* end up being cheaper, more powerful, and leave you with more options for future mods too than a very rare & limited SC-V6 would.