[Jon Stratis]

If I understand the description correctly, the plywood on the bumper in question would not touch the frame perimeter at all - it would be 1" off it, with the brackets holding it in place being the only part to touch.

This really, really does not meet the intent of the rules, and as an LRI I could easily point to many of the rules referenced in here. But really, I think it comes down to R26 and figure 4-9. Figure 4-9 shows the bumper plywood resting along the robot frame, but there being gaps in the frame. The intent of the rule is to allow those gaps in the frame of the robot. It is NOT to allow you to essentially have an oversized robot. As an example, lets take it to the extreme... what if I build a set of bumpers with 6" deep blocks on the back every 8", and attach that to my frame perimeter? I'll end up with a robot that, when interacting with other robots, has an effective frame perimeter of 168" - it would be HUGE. Clearly, that's not what we want on the field.

I also would not consider a 1"x6" "clearance hole" to be "small", and I would suspect that something that large would "significantly affect the structural integrity of the BUMPER", as described in R21-A. The intent of the clearance holes in R21-A, as I understand it, is to allow a flush, rigid construction of the bumper. It's so you can account for any bolt heads or slightly protruding axels and still have a bumper that is snug and tight against the frame perimeter. It's not so you can get more motion in your mechanisms.

I strongly suggest looking at any options for moving that motor to a better location.

Edit:
You could also ask a question on the Q&A. Something specific, like "Is it legal to have a bumper mounting system that holds the plywood 1 inch outside the frame perimeter, so long as there are hard mounts to the frame every 8 inches?" Asking a very specific and clear question like that and getting a positive response is really the only way to be sure you'd be fine at competition.