The question title pretty much sums it up, but has a bike with an alternate drivetrain style like this been made?
This would mean a derailleur mounted essentially upside down with the tension pushing the chain upward. I could see where this would protect the derailleur and keep the chain out of the way from dust and debris more. However, I could also envision some issues with front shifting due the the chain coming up from the front chain ring as well.
Pictures would be much appreciated!