I'll offer preinstalled systems (US region) and an install service (you send in a 3DS, I install the board and send it back). Sorry, I can't offer premodded systems in other regions (JP/EU).

Details & limitations. Read before you decide to buy.
* Video from both screens are output over a USB connection.
* For original 3DS only, not 3DS XL/LL.
* Supported OS: Windows XP / Vista / 7. There are no system requirements other than a USB 2.0 port, although a fairly recent multi-core CPU is recommended.
* Software can record .AVIs, take .PNG snapshots, or just be used as a display.
* Only video is output over USB currently; audio must be recorded from the headphone jack. The board is capable of doing digital audio capture over USB but it isn't supported yet, it'll be made available with a firmware update later.
* Only 2D video is output for now. 3D capture is planned for later.
* The card does not appear as a standard capture device (like a webcam, etc) to other software; you need to use the provided viewer software (link below). You can use another program for recording or live streaming, but it needs to be one capable of doing screen capture (Camtasia, Fraps, XSplit, etc).
* The software currently uses VFW (Video For Windows), an ancient API with some limitations, like 2GB AVI size limit and smaller codec selection. Files are split automatically, but there can be a small skip between them if you stitch them together. You can get around this by choosing a codec with better compression or use some other screen capture program for recording that doesn't have a size restriction.