The main problem with trying to put a Roots-style Eaton blower on top of a 5.0 is that the distributor at the front gets in the way of the nose and the drive snout of the blower. BBK made a kit for 5.0 Mustangs that mounted an M90 off to the side, sort of like a Paxton or Vortech, etc. And Explorer Express markets a kit for 5.0L Explorers that puts an M90 on top, but the Explorer / Mountaineer is the only OE 5.0L application with DIS rather than a distributor, so they just move the coil packs over to the side out of the way.
So the short answer is yes it could be done, but not easily.
cheers
Ed Nicholson
SCCoO