Okay, after spending a few minutes staring at the catalog listings on Rifftrax.com, I can say the following:
1) There are 10 rifftraxs per page.
2) There are 4 pages, with 9 on the last page.
3) NotLD, Plan 9 and Nestor are in the catalog. Swing Parade isn't.
At this point, I'm considering renumbering them in the order that I watched them, which should confuse pretty much everyone.