I know you could feed flower beetle larvae to tarantulas but how about rhinoceros beetle larvae?
Except that it takes a heck of a lot more effort to breed rhino beetles than feeder roaches or crickets...Just fed an L1 larvae to my GBB tarantula. Seemed to not mind it. I kind of felt bad but you have to think; if you do it with crickets or other feeders there really is no difference.