I have an F250 with the shortbed...I bought the Demco 18K autoslide
as seen at the link. I have a 2002 Holiday Rambler Alumascape...when I bought it the guy threw in the hitch, which was a Reese manual slider. I could never get it to slide so I bought the Demco because the Demco needs no 'key' (capture plate) which means I can pull anything with out worrying about finding a proper capture plate.
Apparently the guy I bought the trailer from couldn't get the Reese to slide either, as both sides of his cab had the 'beauty marks' where the trailer punched his cab in - no damage to the trailer, though.
On our first trip we were in a strange town and I turned onto a street that was a dead end and I had to turn around. I had the trailer to 90°, maybe a skosh more. When we got back to the main road I told my wife the hitch just paid for itself!
Oh - watch the video in the above link to see the hitch in action. Click on the video tab at the bottom of the hitch picture.