New picture (thats me driving, dressed as an escaped convict):
Addressing a few of Jay's questions:
I don't think we have tested Blockland Retail on a mac yet.
I don't understand your second question. If you want to bind different keys to different commands, like using ijkl or the arrow keys to move, or the mouse to place bricks, you don't need any special mods, there is a setting to change controls in game. If you mean non-standard keys, like volume/cd-drive controls, 4+ mouse buttons, or extra keys on foreign keyboards, I think you might have to edit the engine or something. I really have no clue.
You should be able to edit all files fine on a mac. Whether you will be able to run the game on the mac to test your changes or not, I'm not sure, but I'm fairly sure it was Badspot's intention to make Blockland compatible on both Windows and macs.