Trust me, at that point you're just going "crap, what *else* might crop up for potential customers for my games am I'm missing"
So, fiddling with either of http://i.imgur.com/dRyPJIc.jpg
have any impact on your end?
I honestly tried every combo of settings and formats for the textures I could think of including using alpha decals.
It could very well be that it's a single card/driver combo and in the proud tradition of broken clocks and blind squirrels I stumbled across the solution for my card.
If no one else can repro then it's not really an issue
I'll revisit this when I get an Nvidia card.
Sorry for the wild goose chase.