SmallHD DP4 during my stay here in the States this month. I paid $30,- for 2 batteries including travel charger, car charger and express shipping.
The batteries do not display information to the camera but since I am solely using them for my monitor, I don't need that function. And I hate to pay for something I don't use.
These batteries are 2200 MAh, which I believe is more than the standard Canon 1800 mAh and I confirm that they work ;-) The question is, of course, for how long. Time will tell.
For now they power up my DP4 and I've had the pleasure to shoot some video with the battery-powered monitor, my GH2 and my new Super-Takumar 50mm 1.4. I love this lens already- will post footage tomorrow!