Thank you--I definitely don't remember that thread, nor posting in it.  My memory of these things is just plain bad.

I looked at the first four pages of it and was looking for a flat-out denial from PrimeNumber7 that he isn't an alt of Quickseller and didn't see anything of the sort.  Quickseller even posted in it and also didn't deny it.  That says a lot, and that's in addition to the evidence you presented in the OP of that thread.  So fuck me, I got snookered. 

To answer my own question as to why Quickseller would need to rank up an account to Legendary:  He's likely trying to start fresh with another account that doesn't have red trust so voluminous that it could paint a street full of houses--but as with his other alts, he basically got caught by his own writing style. 

Thanks again for refreshing my memory of this.  I rescind my congratulations to PrimeNumber7 and everything else I wrote that was positive.  QS might not be scamming anymore, but he sure as hell hasn't gotten any more honest.