I apologize if I am mistaken, but wasn't it the OD-2 that you were considering, not the OD-1? The OD-1 is the larger of the two and is a frame lock with only one side in G-10, while the OD-2 is the smaller one with a liner lock, and glass-filled nylon on both sides.
Hey, what about the Kershaw Ener-G? It is discontinued, but still available from a number of places. Like
gpknives.com for example. I know its a few bucks over your $40 limit, but there are a few
NIB ones on eBay for closer to $30...
I own this knife, and I can definitely say it is an excellent piece. Granted, I don't have anything even remotely high-end to compare it too, but out of the box this knife was perfect. Perfect lockup, perfect action, perfect build. Needless to say I was very impressed with this knife that I only paid $30 for. Obviously though I can't guarantee that everyone's experience with a certain knife will mirror my own...
The Ener-G is similar to the OD-2 in that it has a disconnected flipper. I.E. the flipper isn't physically part of the blade. The descriptions I have seen call this: Lee Williams patented "pseunetic" opener. It is a little bit bigger than the OD-2, but a bit smaller than the Zing. It comes in several versions that I have seen, including: Gray G-10 with Trac-Tec inlays, Plain Black G-10, and black coated or satin blade finish. It is USA made and has the 14C28N steel (or possible some in 13C26N, from 3-09 or earlier). Here's the link to
Kershaw's official product page.
Anyway, just thought I'd throw another knife into the mix for you. Just to make it more confusing.

But, like I said, the Ener-G is a really nice little knife, and worth taking a look at, in my opinion anyway.
Because I own an Ener-G and a Zing (tanto), here are some pictures comparing the two (click images for full-size versions):



