Converted Genestealer Cult Armies in Warhammer 40K - How Far Down the Rabbit Hole?

Warhammer 40K has always been a creative hobby. While Warhammer 40K is a game, it is a game where the player has to at least build the playing pieces on their own. Most people paint the playing pieces as well (and this step is generally required for major tournaments). However, some players don't stop there, they heavily convert or even scratch-build forces to create a truly unique army. I've frequently posted my converted Astra Militarum forces that I run alongside my Genestealer Cult as a separate Brood Brothers detachment, but why stop at just Astra Militarum?