Now that we're starting to see GameCube hacks, I'm going to guess these are going to require downloading "scene" ISOs (which were hacked to massively reduce the size. Pure GameCube (and Wii) ISOs, such as dumped through a Wii with homebrew are a constant huge size (though at least untouched GC ISOs can compress somewhat, Wii cannot it seems).
Well, you can reduce the size of GC and Wii games.
For gamecube you have DM Toolbox or DML Conv (others are not very safe, like Gamecube Iso Tool) that remove the garbage data and give you a working, smaller ISO. They are pretty easy to use.
For example Wario world goes from a full gamecube ISO, 1.35 GB to 260 MB. Depends on the game of course, some are not even worth trimming.
That said, the PAL 60hz hacks (Or the Skies of Arcadia mod) were made to be applied on clean 1:1 ISOS... But the IPS patch also works with trimmed isos (As I tested it, and worked both on Dolphin and on my Wii) as long as they are good dumps, because it doesn't have checksums.
I thought it was easier to find the clean images than finding trimmed games. In fact I went to the RHDN IRC to waste others' time asking several things just to try to be as convenient as I could, lol.
For Wii there's a disc format named WBFS that does pretty much the same, removes unnecessary data, gives you a smaller file.