Looking for a clamshell-style Mk3 cargo bay door?

[fourfa]

I'm looking for a mod or part pack with a specific design cargo bay door, where it splits open symmetrically, clamshell-style.  Like this on the real-life C-119 cargo plane:

Objective being a vertical-landing ISRU mothership.  Based on a vertically-oriented Mk3 central stack, this door would be at the bottom and conceal the ISRU drills and crew egress.  I'm currently using the stock cargo bays but don't like the asymmetric mass of the drills all on one side.  I know I can mount the drills symmetrically and just have them clip right through the solid bay walls, but I hate that.

I tried the shorter Mk3 cargo bay ramp from SXT, no help there.

Thanks for any pointers!

[fourfa]

Or dead-simple van doors:

[fourfa]

How about an iris style door? Seems very sci-fi, no one has made one of these? 

As far as RP goes, it doesn't even need to contain pressure, just protect my drills from reentry heat