Ok - at that price, I'll almost surely bite! Just a couple more questions, if I may... The rest will sort itself out, I'm sure.
1. Actually, that RX580 of yours is perfect as a specimen : roughly the same tdp as a 1070Ti or 1080 (close enough, anyway) and the same cooler. I know this is wholly subjective, but - how does the card sound, under load? (Sorry - forgot to say, that I was talking about silence under load, inasmuch as that's possible in an sff build...). Understand that there's no real separation between me and the components in your enclosure but I'm ok with that - plenty of components sound just fine open air to me (my Be Quiet fans, the L9i, etc) so not too worried about that, assuming the components in question is quiet to begin with;
2. With an SF450 and one of those Gaming X or Titanium cards (really leaning towards the 1070Ti Titanium), confirm I'll have room for my 2 x 2.5" 860 Evo's?
Barring an answer to that, I think you have yourself a customer! Thanks!