There was a recent mod to make a sort of Rombus from June, and an older thread that I didn't want to necro since the author disappeared a couple months after his post ( @NathanKell responded a few times in that one, we share a similar interest in that particular retro-future, I think).
Anyway, has anyone worked on plug engines of the type that Bono was considering? Is regenerative cooling a thing as far as reentry goes in KSP?
(This image if from William Black's deviantart page. Wow. Great stuff to look at: http://william-black.deviantart.com )