Well I did it again. I went out and bought an A/V multi format cable for the older nintendo systems, playstation 2/3 and original xbox from gameshtepp and a F/F S-video adapter from radioshaq. I then hacked up one of my many S-video cables and rolled the signal and ground wires to properly fit the leadtek card (again aided by breaking the plastic key). Turns out the signals pin positions for S-video and the leadtek's proprietary job are effectively in the same spot, only reversed top to bottom. So, now I have a slightly crisper image on my monitor! Go me?!
Buying a leadtek breakout cable would greatly reduce hassle, but not many places seem to have them. If they do, they'd be in upwards of 30$, with questionable functionality as pictures of them don't usually exist on those websites.
I spent a total of 18$ at the two places, including tax. Minus however much gas I burned driving to and fro. But hey, it's the adventure, not the goal isn't it?