I think if you fuse it properly you can still use one without fear of blowing the xfrmr. Here's some food for thought:
http://antiqueradios.com/forums/view...&highlight=6x5
I've had a crazy idea for a while. Remove the base from a 6X5. Wire in a couple 1N4007s to rectify and a red LED to simulate the filament. Then remount the base and no one's the wiser
