Upload & Sell: On
I have a Maha Powerex, and yes it is the best charger on the market, but that's not what charleychen needs. He needs a charger that will handle whole battery packs, not the individual cells.
This is what I have but it is a little pricey (though cheaper than an extra camera I suppose):
Although you get by with something like this:
As for the correct leads, I'm familiar with the Quantum leads but you would have make you own. It would probably cost you $10 at Radio Shack. You would need to do a bit of soldering though.
The beauty of this method is that you would only need to test on the flashes one time. Once you know that a 5,000 mAh (also called a 5 Ah battery) gives you 250 flashes, for instance, you know that each flash needs 20 mAh. From then on you just need to charge and discharge the battery, figure out the current mAh capacity, and divide by 20 to figure out how many flashes the battery will provide.