Yeah, I've had my MP 1550 for a few months already and used it on several trips, and ya'know, I love it.

EDIT: Ya know, I just realized something. All this time I've been telling people my MP1550 is a 5000mah battery pack (when using 2 x 2500mah AA's), but in reality, it's a 10,000mah battery pack, because 4 x 2500mah = 10,000 mah. Let's see someone top that one! :P

I picked up a solar charger at Costco (U.S. brick and mortar store) for $59. It's a clever design with the 3 wings that open up. It'll soak up the sun and charge my N800 at the same time.
http://www.solio.com/charger/

It came with 6 or 7 electronics tips, so I can use it for all my gadgets. We're planning a safari for next year, so one of these solar chargers is essential.

I have a Philips SCE4420 and it does not work on my Nokia N900 but I modify the cable and now it works!
You ned to short the data line on the cable with a 100Ohm resistor and it works.
see http://en.wikipedia.org/wiki/Universal_Serial_Bus at the Power section.
I bought a male-female usb cable, I cutted and inserted the resistor so I can use the Nokia cable as it is connected to a PC to use my Philips SCE4420.