i dunno, i've much imagined fluffing an ig army after a basic aav platton here irl, with 12 chimeras aka marine aavs, but the problem is unless an army forgets to pack anything about str4, you're just asking for trouble, a balanced army will end up your worst nightmare, since chimeras aint exactly as armored like leman russes, and that penetrating shot, even if it doesn't destroy the transport, will see your infantry bailing out and oh so vulnerable.
in my opinion (no not imo, because that's lazy-type), if you want mech, you're better off just using grenadiers stacked in chimeras, the two special weapons with better BS and +4 armor when they bail out in the open right there sets you off the better. regular guard infantry imo belong in cover with cameleoline, if you want them to advance further than your own deployment zone, than you shoulda given them light infantry or drop troops. also, the chimera is a sad proxie for a marine aav, sadly i can only find 1/72 models and not the 40k scale 1/65 28mm.