I'd rather not go the E-6 route as the expense of having 8x10s processed for a questionable B&W end product seems unjustified.
I did once try to develop some of the Ektachrome in Rodinal and ended up with welding goggle stuff -- completely black negatives. Now, it's just possible I'd managed to badly fog the film before development (long story) but it seemed unlikely at the time, so I went no further with testing. But you're confirming that some of the conventional B&W developers should result in at least SOME sort of image forming? If so, I'll certainly try again.