Ok, here's my work on Dr. Leonard McCoy, also known as "Bones". This is (or started out as, anyway) the AMT/Ertl vinyl kit. 1/6 scale, about 12" tall.

First, the "before" pictures...
The main problem is that the body is too wide - the shoulders are too far apart. DeForest Kelley had a fairly slight build. I also adjusted his height a bit by recessing the boots into the pants. I cut the boots off at the pant cuff, cleaned up the edges and pushed them into the pants, making him about 1/8" shorter. Not noticeable like this, but necessary compared to the other figures in the set.
The correction process...
I cut the body in a "V" at the shoulders, then straight down the center, removing a strip about 1/8" wide. This was done in the back as well. The parts were re-assembled with superglue. I used spare bits from the removed sections as braces to hold the neck/shoulder piece in place. You can see a little of them in the spaces between the parts.
Coming near the end...
The body, puttied and painted, but I'm not at the final stages of those processes. It's enough for the photos, though. Looking much more like the McCoy we all know and love. See the pictures below for comparison.
The head also needed some work...
The original head had a number of problems. The right side of the face was caved in a bit, the hairline was too high and his jowls seemed a little puffy. The "after"shot at right, done by simply digitally stretching the left picture by about 10%, confirmed my suspicions.
These shots of the modified head look more like "the real McCoy". :-)p The head was heated and stretched outwards by stuffing it with newspaper, the hair resculpted with putty and the jowls shaved and sanded very subtlely.