Here is a pic showing the Luke (Echo Base Flight Gear) custom I did, with the alternate pilot parts made to interchange with it:
I've narrowed the pegs on the knee, elbow and waist joints so they can be easily swapped. I would make all the individual figures for these, but I would need to sacrifice a few more Rebel Ground Crew figures to achieve that, and I quite like the idea of this being a kind of 'ultimate Luke pilot set'. (I should have put the 'Heir To The Empire' helmet in there too.)
I have recently done the ‘Splinter Of The Mind’s Eye’ version. This was made using a repainted torso and arms from TBS Luke Dagobah. To try and get a better look to these arms, I have filled in part of the elbow joints and sanded them down a bit; taking off the square edges. They still have as much movement as before, but now have a smoother look. I think they now look more like arms and less like a bundle of joints. The holster is just a temporary one and is the cut off piece from the TBS Luke Dagobah belt; which I used for the Luke snowspeeder version.