Just an idea: I normally set the SLICKEDITCONFIG environment variable (on Windows 7 x64) to point to my choice of a config directory, in which I then manually set up folders via backup & autosave file options dialog. If circumstances dictate another temporary config folder, the command-line option or explicitly setting the environment variable to another value in a command-line console does the trick.
For those of use who'd like to try the Beta products, but keep them entirely separate to the usage of the current released version, I'm wondering how difficult it would be to make the Beta products select the value (if set) of a new environment variable SLICKEDITCONFIG_BETA rather than the usual SLICKEDITCONFIG? These two config folders would be entirely separate, i.e. config upgrades between versions would not copy any data between them, so the internal invocation Slickedit logic would not change after the point at which the config folder value has been determined.