I think what I want to do can best be summed up by the (much more elaborate) KSP Constellation crew module. Really, I just want to leave a bit behind, like the Apollo Lunar Module, but use the same engine for descent and ascent. The Soviet LK is probably the best real-world counterpart. Unfortunately, I can't manage to build it without stacking it (defeating the purpose) or using radial decouplers (defeating the other purpose, as the lander wouldn't stay together once the AM leaves). So yeah, if any of you have ideas for how to accomplish that, I'd be grateful. I'm currently using B9 and KW Rocketry, if that matters remotely.