You can just use a driveshaft with a slip built into it (like a 4wd front shaft type setup) Looks to be the same trans (or at least similar) to what's used in the Cadillac CTS-V and Holdens (Pontiac GTO/G8) they use the bolt on flange too..
I "think" I read somewhere or other that you could use a shifter in one of the blank off plates on the top of the trans instead of the rod type setup.