via gc-forever.com have posted a interesting articel about a HB HDD adapter for the GC:
A fellow Gamecube enthusiast has created a DIY HDD (IDE only) adapter for the EXI bus on the Nintendo Gamecube!
It's a simple device, but something the GC could definitely use .. I know I'd love to see some GC-Linux support for this thing
Best part of all is that once he gets around to it, instructions on how everyone can build one from a few parts easily found (even certain old PS2 modchips can be modified to do the job - it's that easy) will be released.
It's been tested so far with a unofficial modified SD-Boot 0.3, and the speed is quite good in games. I haven't built one nor know how to yet, but I'd say it probably reads at about 1mb/s from the HDD, which is not bad considering the code isn't very optimized. Regardless, I'll add in support for the adapter in the next version of SD-Boot (working title) which is coming up nicely.
Note, the HDD adapter is not a DVD replacement, and as such, cannot be used to play backups. The author has simply modified an older version of SD-Boot to add in support, so the compatibility with backups would only be as good as the software (0.3 wasn't too great).