I have the following ISD 1000A chips, still in the original packaging!
ISD 1000AP 9537 51SE001
ISD 1000AP 9446R2C046LA
I gather they're both essentially the same thing, and were both sold as Radio Shack Cat. No. 276-1325. I got mine from Liquidation World for $0.50 each. You might try where you live if there's a Liquidation World near you - they got all the old stock that said "Radio Shack" on it when the store became "The Source" here in Canada a couple years ago.
If that doesn't pan out, let me know and I'll send you one of mine for free! I haven't had a chance to tinker with them yet, so you might be able to return the karma when I hit you up for some questions about how you got it working later down the line? PM me if you're interested, ssylee, and we can work out the details.
Ironically, it was my birthday today (February 20th)!