I know this thread is stale and I'm dragging it back to the front, but I wanted to thank the OP with a reason, more than just the thanks button.
as far as usefulness...
I want to pick over some of the library bits of this stock GB ROM from a phone first cousin to mine (different CPU chipset, so binaries no good, but lib files may be of use since both thunder(x) boards.)
See, LG hasn't released GB .kdz or .cab yet for my phone board Thunderc, much less a GB production model to get a dump from; though its big sister phone with same hw board LG has released GB source for, it is missing some libs, etc. Cyanogen only goes so far there, some bits in those libs don't match new kernel.
I really didn't want to unpack a .kdz of the stock p500 GB myself just to experiment, so this zip format is very useful to me.
I'd have dealt with the .kdz if I had to, but you have saved me much hassle booting into the dusty relatively unused m$windoze partition on my computer to use software not available for linux.
Thank you OP! (and yes, I used the thanks button too, but I wanted to tell the haters another reason for this being useful... so thought I'd also type thanks as well as using the button since I'm posting anyway.)