I don't know how kosher it is, but I used XPL909's to replace a failed RCA410 on a PL700-II I rebuilt. I had the pile of them that I had removed when they got replaced with the MJ21196. After fixing some problems on the driver board that were not related, it was stable, did not oscillate, and passed all of the service manual tests with flying colors. Initially it had problems, but I chased them back to some failed resistors and I think one bad diode on the driver board. The resistors in the Zoebel network were also off value.
I killed the driver with a slipped test probe. One had been replaced with an actual RCA 410, and one was some random ECG part. All four are now XPL-909 transistors.
If you need one, I believe I have one or two good RCA 410 transistors left over from that project, and a number of XPL-909's as well.