Don't panic yet.
Dell reversed course on some of their proprietary stuff (like the OEM Windows OS compatibility) and even if their power supplies are still special you can:
check with Dell about an upgrade
look for after market "Dell Compatible" power supplies
When I was in the local computer super center (Fry's aka
www.outpost.com) I noticed they were stocking many different size and form factor power supplies.
Check the Dell manual and see if it shows the power supply pin outs and compare them to the ATX standard ones. If you can't find the ATX pin outs PM me and I'll dig it out. I saw it in one of my manuals. Also look at the label on the PS or in the manual and see what the output ratings are. +5V (25-30A), +3.3V(12-14A) and +12V(8-10A) are the critical ones. If they are in (or above) the current range I showed you might be ok.
In the mean time just pull out the extra drives until you get the power supply sorted and make sure the case is well ventillated so the power supply intake air is cool.
PS Ask SAZAR about the supplies. His brother works for Dell.