Doesn't the Slimblade have trouble remapping the top 2 keys?
A little bit if you use Windows (Linux is fine, dunno about Mac).
For Windows (tested in Windows 7 64-bit and WinXP) you can use the hacked version of the software
here. See
this thread for details on the japanese.
To use it. Just install the version of the Kensington software v1.00. Copy the two exe's from the website (SBT4ButtonPatch100.zip) to the software installation directory (i.e. C:\Program Files\Kensington\SlimBlade Trackball). Then run SBT4ButtonPatch.exe. Restart the software, then use SBTConfigurator.exe to change the top two buttons.
I only really needed the Middle Click, so I haven't really discovered what X1 and X2 are for (maybe when work slows down a bit).
Overall, I'm really liking the Slimblade. I really like the scrolling mechanism.