Hmm. I suspect from your tone that no answer is going to satisfy you, but here goes.
If you really want to know, on the project in front of me right now I've got two instances of BFD2, with around 3gb's worth of stuff in ram between them. I've also got an EWQL Symphonic Orchestra currently taking up about 1gb, and that's going to go up as I work into it. That's the bulk of it, but I also have five instances of dimension pro with bits of this and that going on. So that's about 4.5 gb of samples sat in ram. This would be pretty hairy in a 32 bit setup, lots of virtual memory paging and whatnot, so lots of risk of drop outs and stuff.
I've only got 6gb in my computer at the moment, so I'll probably need to start freezing stuff soon, but for now, it's holding up admirably well.
Both BFD and EWQL are the 32 bit versions, running under bit bridge. I'm not sure how this makes the argument bunk.