VT1100 and VF750C discs have the same part number. There's some very decent ones on US ebay for reasonable money, but by the time you include postage, VAT, and the Royal Mail handling charge, not so cheap.As far as the disc goes. Honda used the same bolt pattern on lots of stuff, so the disc from one of the years Shadow 750 used a single disc of the same diameter and bolt pattern, but a different look. I used one on my FT500 with a 17" wheel. I got it on e-bay for less than $25. It was in great shape as it hadn't been used hard.
I'll have to keep looking for now.