Well, in the end I just wrote it myself. Pretty simple really, just one line of sql to get the data, one line to pass the array to smarty and a few lines of code in the smarty template to display the products. Works like a dream. Take a look and feel free to comment:-
http://www.adultebookshop.com/Maddy-Becomes-A-Pony-Girl-p-302.html
Saved me $39.95