After trying many different keyboards during a period of a few years, I have settled on two rather disparate favorites: the IBM Model M SSK and the HHKB Pro 2. It is difficult to choose between the two boards. For example, I prefer the HHKB layout, but I favor the feel of the buckling spring switches in the IBM. Therefore, I decided to remap the IBM keyboard in the HHKB configuration.
My setup includes three computers, one each running Mac OS X, Linux Mint 13 64-bit Xfce, and Windows 7. The computers share a keyboard and mouse via Synergy software, using the Mac as the server and the other computers as clients. Remapping the keyboard was easy, thanks to the great free program, KeyReMap4Macbook, and the built-in keyboard preferences in the Mac.
Following software remapping of the SSK, I swapped some keys from a 122-key IBM terminal keyboard to reflect the new key assignments. Shown below are two views of the modified keyboard:
1. Right side of keyboard, showing the new Backslash key (\) that replaced the former Backspace. The < key next to the Backslash is a dummy key to fill the space taken up by the former Backspace stabilizer. The dummy key is held in place with a WASD red O-ring slipped over the key stem. The new Backspace is the ---> key. Reset= Right Command and Alt = Right Option. Right Command + Right Option = Fn. The new Fn key combination enables various HHKB functions, such as the cursor diamond, [ / ; ' and F-keys, such as Fn +1 = F1.

2. Left side of keyboard, showing Ctrl ("in the position that God intended"), replacing the former Caps Lock key. Alt = Left Option; Enter = Left Command.

Now I have the best of both worlds: IBM buckling springs and HHKB layout. Moreover, this modification is completely reversible by switching to a different layout via software and swapping the keycaps back to their originals.