Yes, there are several.
A search of "Windows shell replacement" will get you some of the more popular including Litestep and Aston.
I tried a few a while back, but they all felt lacking compared to explorer. The smaller memory footprint was nice, but not that much of a savings...and I can save it all by closing explorer and running programs from task manager.
They all install and remove fairly easily, though I would make sure everything is backed up first. You are playing with a critical part of Windows..better safe than sorry
