Need ideas for orky plasma guns

So in my Inqwaaaghzishun army I've been using Kustom Mega Blastas as plasma guns in my henchmen squads..I find myself needing 4 more of them and cant justify paying the outrageous prices for them on the bitz ordering sites...so at that point decided I would make my own... but quickly found myself stumped for ideas on how to go about scratch building/bitz building an "orky" plasma gun

so here is the kustom mega blasta I've been using


and here is a standard imperial plasmagun


anybody have any ideas or thoughts??