Thanks for such a helpful reply and contributing to the thread.
I might as well comment on this too...
If the computer is going to someone who isn't tech savvy, they're not going to have a good time if something goes wrong inside of OS X. Generally if you choose the right hardware you won't have any problems. However if something happens to the OS X install and it needs to be reinstalled, it's not always as easy as reinstalling Windows and they might give you a ring for some tech support.
OS X can take some time to get every piece of hardware working as it should, there's a lot of configurations in system files, setting some flags to true/false, etc. Just throwing it out there.
Understood, but I don't make it a habit of turning down customers. Even If my profit margin is only 100 bucks, thats money towards overhead, so ill take it. He is a bit tech savvy, and knows this is gonna be complicated, and understands if everything is not 100% spec on the Mac side.