I don't have a linux install available right now to test this, but if I remember correctly I think I used the cut command for this a while back. Basically what you do is to zip the file as you normally do in to one big file and then chop it up with cut in desired sizes.
When you want to extract it you would use cat to concatenate the choped up files back in to one and then finally unzip it as normal. Something like "cat file1 file2 file3 >> myZip.zip"
As I said, this is untested but it feels like it *should* work
---------- Post added at 07:33 PM CDT ---------- Previous post was at 07:02 PM CDT ----------
Maybe the command is "split" and not cut when I think about it...