The only keyboards I know of that has specific Mac-compatible software are from Razer, but I wouldn't go anywhere near those. A few mechanical boards have the ability to use Mac layouts by changing hardware DIP switches. Examples include the KUL ES-87, Ducky Shine 3, and WASD CODE. The CODE is probably the most Mac friendly of the lot, but you have to want either MX green or clear switches since those are the only two available for it.
Otherwise, you can use a system preference pane in OS X to alter the layout of a standard Windows keyboard. You can interchange the caps lock, control, alt/option, and command keys to do any of each other's functions (eg make the control key command and vice versa). You can use this to make OS X essentially mimic the way a keyboard would work in Windows, which is especially handy if you dual-boot.