I'm probably seeing the problem more because I only race spec classes so the Novak 25.5 and 21.5 are the standard. They aren't the smallest can's out there + the sensor wire is on the left rear which makes maneuvering around the left brace a little dicey. maybe I can describe the idea. I have no photoshop skills.
1.Eliminate current location of belt tensioner.
2. eliminate left rear brace section.
3. Use a simple aluminum standoff (round tube) as brace for left rear.
4. Relocate standoff towards the left side of chassis.( don't have actual measurement but enough to provide more room for forward motor movement and sensor wire clearance.
5.A new upper deck would be needed. The only modification would be a redesigned left rear "ear" section to extend out to the new standoff support.
6. A new upper brace section would be needed. Again, because of the new location of the standoff. The rearward mounting would stay the same.
7. A new belt tensioner could be mounted to the chassis somewhere closer to the middle of the belt which would equalize tension pressures. ( to picture this, imagine a aluminum piece mounted to chassis outboard of belt. At the top, the tensioner pulley would face inward and contact upper belt. Naturally, the tensioner wheel can be moved up or down to adjust tension.
Just a thought that seems like it wouldn't take to much to do given the skills of someone like YoDog.