I decided I wanted a smaller Windows partition and larger Mac partition, but I didn't really feel like wiping my Boot Camp install to do so.

I've used Gparted LiveCD in the past on several PCs, with no issues. According to the site, it works with most/all x86 hardware. Seeing this, I downloaded the latest build in order to resize my NTFS partition and extend my HFS+ partition. Gparted is supposed to be able to do this.

It was able to see all the partitions on my HDD, so I told it to shrink my NTFS partition from 40 gigs to 30. In doing so, that 128MB of space Boot Camp leaves between the partitions would become about ten gigs of space. Everything seemed to go fine.

Before trying to extend my HFS+ partition, I decided to boot Windows/Mac up to make sure nothing got fuxored. Lo and behold, my Windows partition doesn't show up when holding option on boot.

The data is still there, as I can see it in Mac OS and mount it read/write with MacFUSE. Just can't boot Windows for reasons unknown. And Gparted wouldn't let me extend the HFS+ partition to fill the free space, and gave me errors when I tried to put the NTFS partition back to its original size.

It's all a moot point now, as I used Boot Camp to delete the partition(thank god it worked still) and started over. But why would this have happened? I didn't think EFI would have a problem being able to see a second partition after a large amount of unallocated space, but it can't see it..

EFI isnt the problem here, but rather GPT. GPT (GUID Partitioning Table) is a replacement for the aging MBR (Master Boot Record) system used on x86 PCs. It writes valid MBR information to where MBR-based OSes or programs expect to find it, for legacy compatability purposes. However, a side-effect of this is that disk utility programs like gparted think they can modify the MBR information, whereas in fact it is overwritten by GPT.

Sounds like gparted tried to dick with the MBR info on the disk, which confused GPT, leading to a non-bootable windows volume. Sounds like you recovered ok, but this is a good lesson for others: only use utilities which are GPT aware to prick with your (real) intel mac's disk.

(NB: GParted is 'safe' (relatively speaking) to use on a hackintosh system, as they all use MBR).
(NB2: Unless you have multiple hard disks in use on your hackintosh, in which case you might be using GPT on any non-boot volumes. Use Disk Utility to check. For example I have a 100Gb boot disk using MBR, and a RAID-1 mirror using two disks which use GPT.)

Is there any open-source/GNU (read:free) partitioning software that IS GPT aware? Backing up and restoring images takes several hours (and is really :censored2: annoying), and I have next to no money of my own at the moment for a utility like iPartition.

You could try gdisk. I'm not sure about what features it has, but I used it to print out MBR and GPT info about my disks.

I'm not sure if there are ANY utilities that can resize a Boot Camp partition and still have it work.