Brian, I have not seen anyone mention this. It would have to have a wider base configuration. Unless you made them real big, i think this would put the driver too close to the floor.

I don't think it would be a problem for the woofer, but with these being full range drivers, i think that, for upper mids and treble, they should be a bit higher. Just my opinion.

The Point of the Open Baffle is to let the drivers breath both front and rear. which creates a better sound stage and almost holographic sound. Placing the driver horizontal will pretty much destroy the back wave being able to breath it may also induce cancellation of parts of the front wave as the reflection off the floor will get to the front much faster than say 3 feet off the front wall