Have you searched the forum for the different window managers available, for instance:
xfce4
rox
e17
icewm
fluxbox
and so on.
Whatever kudos there might be in having a look n feel like OSX, for me it is important to have something that works just as well. So far I have found xfce4 combined with rox is really more intuitive and configurable than anything else I've used, quite like the Finder on the Mac. There is a howto here:
http://users.telenet.be/zaurususer/Chero/(Also look for the thread on xfce4 finetuning... it's getting a bit long now, but which bits are relevant to you will depend on which Z you have and which rom you are using).
If you try out different window managers remember to back up your .xinitrc file so that if things go pear shaped you can restore the default back again.
Remember to have fun. You're doing stuff you can't do on a Windows mobile device.
