That'd be what we call a "206" bridge, or a G5C in the case of the 5-string. They've been discontinued for quite some time, as far as I know. We're having a special run of them (the 4-string version) made just for us, we should have them in a couple of months. No spare saddles lying around, though.
I do have a few 5-string bridges like that that, but the price is kind of scary....

If you're hurting for one bad enough, we can help you out.