you can boot games from usb now mate you need to format to fat32 then use this
link
to change the drive to wbfs i think it is theres been loads of differnet loaders about think theres one in the stickies in the wad post, the app in the link i posted also lets you dump the games to the hard drive/pen it scrubbs them and takes out all the dummy files so the game ends up smaller i have 22 games on a external
hdd and its taken under 50gb well worth a look mate ive stoped burning them to discs now.
i think theres just the one cios file you need to install for usb support then your good to go. its mad i think its wii sports when you put it on a
hdd its only about 150mb.
this post
link has all the files you need instead of using the wbfs tool in this you can use the gui i linked above theres a quick tut in there too if i remember right.