Check out the Fourth Element Proteus Short John - Proteus Short John - Shorty Diving Wetsuit : Fourth Element. You wear it UNDER you wetsuit. It is paired great with their semi-dry, but would add warmth to any full wet suit. I have a friend who dives the Proteus semi-dry with the short john and is fine on dives when the rest of us are in dry suits.
The system together is awesome.
The system together is awesome.