Thanks for all the comments!
I do realize that OP2 doesn't have much demand in the Apple side of things, but it could help expand OP2 -- after all, OPU does get new members on a regular/semi-regular basis.
It's size is due to the inclusion of Wine, not due to the AVI's and the OP2.clm file. I'm working on reducing it's size. OP2 isn't so complex and demanding, and therefor probably doesn't need ALL of the Windows APIs to run well.
AmIMeYet: Yes, OS X can natively grab transparency from it's windows, images, etc.
So, my to-do list so far is to fix the networking issue (I've figured out what it's doing, I just need to fix it. Fortunately it's minor.), reduce the size to a manageable level, and figure out a way to distribute it easily once it's finished. Maybe I should ask Lev or Blackbox. (Not sure who's in charge anymore.... been out of the loop too long, lol.)
After I fix the couple issues with the OS X version, I'll work on a Linux bundle. However, as it has been pointed out, it may not be necessary to do so. Nonetheless, it couldn't hurt. There are many other OS's out there that could benefit from this. And other OP-themed projects as well.
Edit: After compressing 'Outpost 2.app', it's size shrunk from 265 mb to 75, just using the .zip format. Putting it into a DMG would probably compress it further, so it's size may not be quite a huge issue.