Hey Digipimp,
Is it photos or movies you are after?
If it's images this is going to be hard. Alot of what you see are skans from books. Some of the large scan sites have a license to do this, but others dont. Cuty Mask Melon, the image you posted is one of the largest sites, and has some great content.
We deal with movie content, and as you are aware, this content is pretty hard to come by unless you have partnerships with some of the Japanese Producers. Thankfully we do. However, it is difficult to get hold because Uncensored porn is illegal in Japan, and therefore alot of the Idol content you will find has a mosaic over the "interesting bits".
We are getting some exclusive idol content made for us, but it is costing us a fair amount.
The best bet would be for you to contact some of the Producers and see what they say. Kuki, Cosmos and Cherry bomb being some. Webgurl also moderates a great Asian Message board, you should find something there as well.
Good luck