Norman Challenge for Mac OSX
Take the Norman challenge! I'm so interested in your success, I've bundled an alternate Mac installer which includes Asset, Minimak, Norman, Qwpr, and Workman. Combined with U.S., Dvorak, and Colemak already on recent versions of Mac OSX, that ought to give you a similar pool of layouts to compare against Norman. If none of them suit your needs, you can use Ukelele to import and modify one of the layouts to your own liking.
Once you run the installer, you may need to log out of your Mac or even restart for the new layouts to be noticed by the Language & Text options.