One truck, two MC#'s ???

Theoretically, it sounds possible. You would already have liability and cargo in your name in order to obtain your authority. Keep paperwork & permits for each carrier separate in the truck. For name and dot#, you would need removable stickers that are easily switched. Just switch stickers to whichever carrier has the load, and file any accidents/reports with whichever carrier the truck was with at the moment of the incident or inspection.

Seems way too complicated to even attempt, but theoretically it sounds possible.