While I like the idea, I'd rather telecommute on the fifth day instead. Small kids at home, so my wife would not want me to gone from 7am to 8pm. Plus, they're small only once.

While 5 day workweeks are kind of a pain for adults, I think 4 day workweeks might hurt kids more--it's that much more time lost with mom and/or dad. At least for some families, I should say, like mine.