Can you not find a half height gfx card on the net some where? Or was you board on this project µ-ATX? That thing looks like it should work though.
coolio. i always wanted something like that.... no idea about alternatives tho
Basically changing the signal from VGA to RGB scart is a pretty complicated process, especially if you want any kind of picture quality.
Similar to the one you posted is the Logic3 VGA Box.
If your TV (or video equipment, etc.) has component video input (different to composite video input), then you can use a VGA->Scart direct cable.