I've been having a lot of fun old-school kit-bashing to build genestealer hybrids for Space Hulk. Each of these three guys uses bodies and heads from the Stargrave Scavengers set. The two on the outside each have one arm taken from a modern genestealer hybrid set and one arm, or at least part of an arm, clipped off a classic Space Hulk genestealer! The middle guy has one arm from the scavenger set, but the gun arm comes from the Wargame Atlantic Einherjar (space dwarf) set, a sprue of which I got with a copy of Miniature Wargames. Makes a pretty good plasma gun!
Space Hulk uses genestealer hybrids in a way that really warms my gamer heart. Each scenario has its own encounter table, so you really never know exactly what equipment your hybrids will be carrying, and since this can very greatly from scenario to scenario, you never really know how many and what type you need in your collection. My goal is to have about a dozen of these guys with varied weapons, so I'll always have something 'close enough' that I can throw onto the table (hybrids rarely last long anyway).