I'm describing the feel that you get with "mechanical-switch" keys (google it for images/explanations). The Apple Extended Keyboard (and Apple Extended Keyboard II), and, more recently, the Matias Tactile Pro (not ProTouch, whoops) are two keyboards that use such technology. Most other keyboards do not.
The Razer "for Mac" keyboards seem to have obviously non-Mac layouts, which rearrangement won't fix. That's a deal-breaker for me. The correct layout and the feel of a good keyboard is more important to me than additional keys or whatnot. My question was mostly due to curiosity.
I'm not sure what 'layout' issues you are referring to, but I'm not a Mac user and I have trouble adjusting to any laptop keyboard. I'm guessing that the layout issue is that you need four bucky keys to the left of the space bar and two to the right, instead of 3/4? Or is the location of the arrows and lack of the right half also critical?
EDIT: Mechanical keyboards can be tactile, noisy, both, or neither, depending on the specific nature of the switch. Which are important to you?
EDIT 2: What feature does the Matias Tactile Pro 3 keyboard lack that a 'gaming' keyboard would have?
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.