I thought that there was a $user$ evar built into LS....
I cant check right now sooo....

But if there was :

You caould create a "Substitute" Step.rc within some folder and have settings like : Include "$LitestepDir$$user$step.rc"
which could branch off and load any theme $user$ wanted...

but you probably, you know this...

damned work arounds.......................................

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