Check ebay for DPS-2000, DPS-2500, DPS-800 , DPS-1520 and Dell Z750P (poweredge 29something PSU). DPS-2500 is a real monster -
http://www.rcgroups.com/forums/attachment.php?attachmentid=4854652 but unfortunately comes without fans. Got it powering a few Antminer S1 units right now with jerryrigged fans on the side.
As for connecting them - got a bunch of quality PCIE cables and butchered them on one end
A multimeter is nice to have but I trusted the internet regarding the pinout and so far it has worked out fine.
Check
http://www.gekkoscience.com/products/server_supply_breakout_board.html and
https://bitcointalk.org/index.php?topic=379677.0 for a nicer way of connecting it all. Oh and make sure you do the homework regarding all those model numbers, you want 12VDC, think some of those server PSU can do 51VDC as well and you probably do not want that.
EDIT - about datacoin - I don't know if they are profitable now. I managed to find 2 blocks soloing and about 15 datacoins mining with
http://dtc.xpool.xram.co . I find the idea kinda neat , seems to serve more purpose than most of the coins here, somewhat like namecoin I guess. So I think of it as a long term bet and I only have an i5 and some phenom 9xx mining it, not much of a running cost there, electricity-wise.