I too have been thinking about different ways to carry while in the vehicle because my strong side holsters were not very comfy for any length of time.
I decided to use a Fobus cross draw because it holds my H&K securely and it is comfortable to wear while driving. It's actually called a "roto" holster because it can be rotated to any position.
https://secure.fobusholster.com/cata...roducts_id=155
Just another opinion..........
Wilkie
