I just finished this tonnaeu cover/Ramp for my F150 short box. All Aluminum (Aluminium for folks back home) checker plate tonnaeu cover & light bar.
The ramp is double slide as the bed rails are about 4'6" & the bed length is only 5'6", so a double slide ramp out of grip strut is welded to the under side of the tonnaeu cover. Fully lockable (as the OEM tailgate is lockable).
I have more pics but have to get them uploaded tonight & will post more pics if anyones interested.
This picture was taken on the way back home from the Outlaw round 1 on Vancouver island last Monday. Pictures in Jasper ational Park with the Rockies in the background.
This is the Ramp inside: