have an orphaned original 20 ohm 515 from an IPC Simplex "W" bass bin. Great playing, and original 20409 cone. Its marked IPC LU-1081. No damage. OK, so we all know that original 515 prices are crazy, and rightly so, but the IPC and Northern Electric branded models sell for a lot less.

I'd rather make a trade. I've seen 604e's in good condition go for between 400 and 650, about the same as IPC 515's. It would have to be in good playing condition and have the original cone, but doesn't have to be perfect paint wise. It's going to be used, not put on a shelf. If you have said 604e (grey and white frame) and want to trade, let me know. Who knows, if you have a matching IPC, you might be able to wait out the low prices now and make a good amount of money if prices do reach parity with original Altec 515 pair prices... pairs sell for more and you can still read Altec under the crinkle finish.