With a gamecube, it'd be best to use a dremel and a GOOD cutting disc, your dremel won't come with a good one. Get a thin metal one,
looks like this, worth every last penny you cheap Costanza.
You'll be using it again and again later, I promise you.
Mark your board with a ruler and a fine tipped marker, score it a bit(or a ton, or all the way through I don't care) with an xacto or similar blade of finger slicing, and then dremel(SLOWLY GOD Dang THIS IS NOT A POWERDRILL) to your hearts content. Sand the sides with a highish grit sandpaper, never thought of doing that before till I read Ashen's post(didn't have sand paper back when I had untrimmed mobo's either, I used a razor blade), but makes sense, don't want inner power layers and ground layers wearing shorts now, you live in Canada, it's clearly too cold for that kind of sporty summer style.
Don't forget to reconnect all the traces you likely severed in the course of your trimming triumph, I also recommend you use regular troubleshooting equipment once you are done, IE a TV and the original powerboard and AC adapter.
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