I believe z4root no longer works on zvc and later versions. Also, I think the gingersnap capability is being updated to work on the mac. You don't know anyone with a PC?
A PC isn't needed for rooting, or applying a custom recovery.
I always have the developer tools installed so it may or may not be needed but you just have to download the android sdk, extract, and double click on android inside the tools folder, and then install the sdk tools. Then the unrooting instructions are followed pretty much the same.
If needed I can probably write it up.
I would be really unhappy if I ended up with a phone that I couldn't mess around with under OS X.