It doesn't exist, but it would be cool if it did.

I believe a OH Waiter was once made, it is in the Annals of Sosak.

Shouldn't be that hard of a mod.

Trickiest part would be making the jig so that when you drill the main blade, you're going in 90 degrees to outer angle rather than to the spine. Tap the hole, put a small stud into it, cut that off flush and polish it. I might see what could be done with a quick tap from the welder or some solder so it can't move, shouldn't damage the temper too much but it is near the base, or maybe just red Locktight.

Reshape the outer liner and scale. While the scales are off (assuming cellidor, not alox) put in a stright pin or two, and maybe a small torx or allen wrench to tighten the stud if needed or make that part of a fob for it. Assuming you do pull the scales, not sure it if would be needed.

Or reshape both sides, and add what used to be called a One Armed Bandit, SMKW has them under a different brand. Given the angle of a SAK blade you might have to get creative and still need to do some drilling.

http://www.smkw.com/webapp/eCommerce/products/Smoky+Mountain+Knife+Works/Kwik%26%23153%3B+Small+Thumb+Bar/KTS1755.html

or http://www.smkw.com/webapp/eCommerce/products/Smoky+Mountain+Knife+Works/Kwik%26%23153%3B+Thumb+Stud+-+Brass/KTS1757.html

Syph made a OH electrician blaxe before. It might be more advantageous to your thumb to make a OH Wenger waiter as they are a bit smoother on the draw.

Wow, some interesting suggestions here. I wasn't thinking of making one, I was imagining how cool my alox Bantam would be if it had that oval thumb loop. But maybe this would be a cool project to kick off with. I've never even taken apart a Spartan, let alone modded anything. Hm... something to think about as the New Year crashes down around us.

Speaking of which, Happy New Year everyone!

Text from the OH Waiter writeup, pictures are in the ether (maybe):

The Swiss Army Gnomes kept me up all night!So here is my newest mod(so fresh it’s still steaming!) a One-handed Waiter. This knife wasmodified specifically for inclusion in a survival kit that never seemsto get finished. My previous strategy for a survival kit SAK was toattach a short “bite” fob or lanyard that could be clenched in theteeth to assist opening the knife in the event one hand was injured oroccupied.

I had 3 Waiters to choose from, the one I chose was without thetoothpick and tweezers slot and had the smoothest action. The reasonfor the handle choice is that I have found these scales are generallyfull thickness with no hollow areas. This was important because itwould have left gaps when the clearance notch was cut for the thumbstud.The thumb stud was made years ago out of ¼’ brass rod for a small lockback. Basically the same concept as the “Bandit” stud, the slot isactually dovetailed to fit the wedge shape of the blade (won’t fall offif the screws loosen) and there are screws on both sides.

The last thing done was to square the corners on the inside curve of the Combo blade for scraping a ferro rod