Suggestion: Until someone writes the :via(Zip) IO layer, have the engineers unzip the logfiles into a directory that has the window "Compress contents" bit set.

If they do this when transfering the files onto their local drives, whether from the network or replacable media, the amount of local diskspace used will probably be roughly the same as if the saved the .zip file.

The advantage is that the filesystem will do the decompression on-the-fly and you don't need to modify your parser at all.