Hello,
1 1/2 years ago we wrote a quite extensive HTML5 and JS product designer for CS Cart which is employed by one of our customers for the past year in CS cart version 2x.
We currently making a couple of changes to make it a add-on and compatible with our responsive designs as well as updating everything to be compatible with version 4.
You can have a look at it at www.schoolbags.com.au.
We should be releasing the addon-on in the not to distant future.
Cheers
Steve