actually, i have! it was a 70's 2X15 fender cab. I cut it down into two seperate 1X15 cabs years ago, and was happy with the results. Basically I just sawed it in half, cut decent quality plywood to fill the empty side, added matching harware as needed, retolexed/grill cloth'd it, and was done.. I don't have them anymore, but i gigged with them many times, and it sure made moving it around easier at the time. in doing so, it destroyed any chance of decent resale, so it's not something i would probably replicate with a vintage cab.