The most sensible suggestion that comes to my mind is buy a TLR and forget about modifying a 35mm camera with all its inherent limitiations of resolution. A 6x6 negative would be getting close to 360% larger than 35mm and packing a substantial amount more detail in your photos.

A few Canon SLRs have IR/LED sprocket counters linked to drive, shutter, mirror and computers. I wouldn't dream at all of tinkering with these. Back to the suggestion of a basic 6x6 to play with.