But seriously: the price of RAM for servers is now ~10$ / G.
It would be nice to see an article comparing all the high RAM machines side by side with specs and prices.
The largest machine I have right now will hold 512G and was a run-of-the-mill machine, it was about $5K, I'd expect the more exotic ones to be substantially more expensive but probably not as expensive as the machines linked here.
(For contrast, that $1K if you'd spend it on HP branded RAM would not even get you four 16G dual rank units...).
5 seconds of googling gets you:
No idea if that will work in that particular server but technically there is no reason why it should not. You can establish a relationship with a distributor to get better prices than those that you can find listed. Those 'call for quotes' things can have two meanings: you're about to be screwed or 'we will give you a better price if you promise to not divulge that we did that'.