OK, so I just obtained a "250" from you-know-whEre and it came with an empty HV case (of course) and NO POWER CORD.

Here're my questions:

1. Can I use the RG power pack from my Strob 500 for the 250? It would be great if I could use both flash units at the same time for studio work.

2. It looks the power cord is different on a 250 than on a 500. What gives? I have extra cords for my 500, but they won't fit the 250.

3. Any idea where I can get a power cord for this puppy. I didn't see anything on Paramount's site that looked like what I need.

Thanks in advance!

Sorry, but the 250 head will not work with 500 unit. The cords are different for a reason, to PROTECT you from having a problem.
The 500 unit has the Storage Capacitors in the base unit and the high voltage (450V)is sent to the head. With the 250 the Storge Capacitor is in the handle and in the base unit you have is a 450v battery, which charges the capacitor. IF you connected the 250 to the 500 base you would supply TOO many Watt Seconds to the flash tube and could have a problem ( Like POW)
The 250 came in two types the HV which used a 450v battery ( hard to get and about $100.00) or the RG type. The RG type had NiCad rechargable batteries in the base, and a cord from a DC Wall adaptor.
Keep an eye out for one of the RG type base units they do come up from time to time.
I made up an AC type with some parts that I had but the 450vdc transformers are hard to find...

http://home.rochester.rr.com/carlvogt/grafstrobe.htm