I got one of mine from these folks...killed me cuz they just happened to be 6 miles away but I couldn't pick it up, they work out of their home.
http://www.originalkeyless.com/2000-...oss-Remote.htm

Got another one on Amazon (used) from "Remote Superstore"...dirt bags sent a non-OEM...I wanted OEM like their ad said...returned that one.

But there's others on Amazon, all used.
http://www.amazon.com/Keyless-Isuzu-...7955957&sr=1-2

All are still in the $50-59 range used. But I did come upon one on ebay a few months ago, like brand new, got it for $15!
And I have the CORRECT programming instructions finally....if you get any that say to open and close the door a few times, and switch key back and forth...they're a bunch of hooey! It's much easier than that.