If there is such a weight issue with bipes, then maybe there could be an amendment to the rules allowing another weight class for competition.
I did e-mail CY Model about the idea of offering a bipe pattern ship and waiting for their reply. Even if it can't get below legal weight, I think they would still be a good seller just for the fact that it would be a unique plane at the field, especially if it is offered in several engine sizes. Say one for a 110 to 120 and one for the large glow or 26cc gasser. Do local pattern contests actually weigh the planes, or is this only done at the larger events? Just curious.