Here's the deal. I want to get the best possible video signal from all of my consoles, and for the most part that's simple - PS3 and Xbox 360 by HDMI and PS2 by component (YPbPr). Unfortunatelly, that leaves the GameCube. I have a PAL GameCube which gives it composite and RGB SCART out, as well as the digital out, which is capable of component, but requires the rediculously expensive Nintendo component cable (they're currently selling for upwards of £50 ($75 US) on eBay, mainly because they were never released over here, so are all originally imports). Now, other than the lack of progressive scan (which is pretty irelevent anyway as all my games are PAL and don't support 480p), the RGB output should technically be capable of the same quality as the YPbPr from the digital out, so I'd like to use it. The problem? I have no SCART inputs on my setup (Sony AV Receiver connected to a PC monitor by HDMI), only HDMI, YPbPr and Composite, so what I want to do is convert the RGB into YPbPr. The other two options are get a Wii (can't really afford it) or buy a commercial converter (which tend to cost more than the comonent cables

Logically speaking, this doesn't seem like a terribly difficult task, and I have seen circuits for VGA->YPbPr conversion which look pretty damn simple, and presumably the sync conversion wouldn't be required as SCART and YPbPr both use composite sync rather than separate H- and V-syncs, so no conversion would be required...at most a composite sync stripper to remove the video signal. Here's an example:

Basically I was wondering if this could be adapted to convert the RGBs to YPbPr. I know enough about electronics to basically understand what's going on, but not enough to tweak the values to adapt it. I would assume the sync wouldn't need to be changed as it isn't being deinterlaced or anything (keeping the resolution, format etc, just changing the encoding), so its simply a case of converting the colour info to luma and difference signals and combing the sync with the luma signal.
Thanks in advance.
N.B. The site that I found that schematic on notes that the resistor by the Y connctor should be 75 Ohm, not 1k