Hi,
Just to establish a starting point, I took that template example from my prior "coffee challenge" and embellished some of your suggestions.
Here's the code at practicewriter:
http://practicewriter.com/vu/?55A1D
One problem with 750 x 500 pictures will be their inability to operate within a 1024 x 768 monitor or smaller view. Normally, I recommend something less than 600 pixel height with a Sophiebox design. I also noticed your listings typically use more than 5 pictures. Most vintage sellers do. I would suggest a minimum of 10 thumbs and this 12 thumb design works fairly well with maintaining the 3:2 aspect ratio for both the thumbs and main image with good alignments.
That "add to Watch List" is currently operating with a link to Google, as it's not a true listing page.
I also added a mouseover treatment lipstick red border for the thumbs.
Danno
Edit: As a comparison, the click to supersize on the UrbanOutfitters page produces a 563 x 375 image with 77 x 50 thumbs. The page design I created uses a 558 x 372 with 90 x 60 thumbs. Virtually identical for the main image, but mine is precisely at the 3:2 aspect ratio for the main and thumb images (no stretch or distortion).