>>95910631
Non-human race hybrids? MORE SPACEMARINES (is that even possible from lore point?)
But more serious, it is kind of hard, true, jump guys make not to much sense with how much mobillity they already have. But some non vehicle machinery or some really big hybrid (ratogre style) or an armieger or knight class vehicle. (in theory they miss a flyer but that does not go to well with the tunnelrats theme.) a "real" trapper. a squad only familiars like grots (or a familiar sneaky hero but the game hates small objektive grabbers i think).