Welcome to Librarium Online!
Couldn't it be explaint in a fluffy manner a really big Ork army (3000 pts?) that some powerfull boss underling of ghazghul had been ordered to go around and find "lost" or new hordes of feral orks on other planets.......cyboars and bikes? :huh:
That's basically the fluff behind my Snakebites army. The warboss's old warband was decimated, leaving him to slowly find and overthrow all of the warleaders of the various feral tribes on the planet. He just keeps the huntas around until they get big and mean enough to be issued a choppa.
As for ruleswise, I'm not sure that that would work in a non-snakebite list, but, eh, it's worth a try. I've seen ork warbands running around with kroot mercs, so who's to say?
"Some days you're the Mekboy building the kannon, the rest you're the grot being blown up by it."
- Quote attributed to Sorkrates, before his much mourned death due to ingestion of Hemsquig Juice.
"Dis iz my choppa, and herez me gun. Dat's for killin' and so'z dis one!"
- Bloodaxe Kommando Warchant
Orks have a tendency to swarm to any big fight, though it is hard for orks to meet feral orks as he fera orks only appear after the normal orks have left the area.