Dont give up....My 3yr old was kind enough to relocate the crank arm on a 36 Colson tandem I was re-doing. Wouldn't have been too big of a deal but the crankset was unique to the colson with a triangular taper where it mounts to the bb spindle. Took a couple of weeks to find it, could have been anywhere, even the trash (or the dumps) but fortunately it was in my box of small scrap metal to be re-cycled and I found it by chance.