OK, so everyone else out there seems to be tearing something apart for fun and benefit of others, so I decided to tear the portable power pack I purchased apart too. Following are pictures of the guts. It's simple to open, since the only 2 screws holding it together are not hidden but are right on the back face for all to see. Once the screws are removed, it takes a little wrenching of the case halves to pry them apart since there are also clip locations. Once apart, I discovered something quite interesting...
The battery they use inside is none other than the exact replacement for the extended battery designed for the D1 & D2. In fact, the battery number is BP7X, and so the standard battery BP6X also fits inside! Woohoo!
Now for the really fun part... I'm going to see if it will support a BIG battery. Considering there are 6,600mAh batteries available for a reasonable price, I'm considering using the circuitboard and cable and building it into a larger case to allow for that big battery. Should work fine as far as I can tell.
See photos below.
UPDATE... I ordered a 3rd party extended battery for the D2 off eBay here 3500mA Extended Battery+Cover For Motorola Droid 2 A955, for $8.01 including shipping, so when done, I'll have a backup battery that can recharge my Droid RAZR twice! The battery compartment is the same size as the D2 battery, so I will simply open up the cover of the charger to allow the thicker battery to extend through, cut 4 tiny slots in the cover of the charger, then slide the extended battery cover which comes with the battery onto the Motorola charger. If I want to go back to the original battery I happen to have a replacement back for a D1, and I can replace the extended battery and cover with the original battery and the D1 cover.