I'm not sure of your timeframe for the purchase, IBM, Sun, and HP are all releasing new or updated 4 socket AMD Opteron systems based on the new Socket F.
From what I can see, only IBM has a 4 Socket system with the new AMD Socket-F on the market right now, the new x3755.
Sun's 2 socket systems have moved to Socket F, but not the 4 socket systems as of yet. Sun has a 4 socket Opteron server with integrated storage - up to 48 disk drives in a 4u server. Sun also has an 8 socket Opteon server. They still have the v40z in the product line, but that system is getting a bit long in the tooth and is just a re-badged Newisys server that put Sun on the opteron map a bunch of years ago.
HP should release the DL385 G2 and DL585 G2 by year end - search around and you'll find press releases and specs on these systems.
I'm making a purchase decision on DB and VMware infrastructure servers this month and considering the IBM servers, but I am looking at the viability of the current generation blade platforms - possibly the 4 socket Opteron blades for my new DB servers.
-- Glenn Stauffer