I looked through old threads and there was a
thread in 2007 that focuses on the
Mclean e90-1 (which I assume is the same one currently on ebay?). In that thread there was controversy saying that there is no way to know if that card is for certain from the e90-1 set since it is a shared image with other sets.
Then I found a more
recent thread in which leon questioned why his e92 miller couldn't be an e90-1. Then some pointed out there isn't a shadow on the e90-1 miller confirming that Leon's miller was indeed not an e90-1.
I couldn't find a thread about any confirmed e90-1 blank backs. I recently picked up a e90-1 blank back Krause (Krause doesn't have a shared image, so is considered confirmed) in the B&L auction that I just showed in the april pick ups. I was wanting to know if there were any other proven e90-1 blank backs?