Not sure if this new information, but you can now buy Nintendo e-shop cash digital codes with no-rush credit. This whole time I was buyin g random DLC and 3DS games with my credit. I wish I known earlier, so I could stockpile credit for 3ds eshop sales.
The cards go from $5 and up
This has been going on for a while - at least since last year. I actually posted about it a few times too.