Do a search on cabinets and you'll find a slew of options. There are a lot of creative guys on this board and they have used some very imginative thinking as far as garage cabinet storage is concerned.
I myself use old kitchen cabinets -- got them for free, and they fit nicely in the garage. I wouldn't worry about metal cabinets being too heavy. Many here have hung them on standard 2x4 stud walls. They paint up well and can be made to look like the more expensive professional storage solutions.
Good luck --