We have towed two different small 5th wheels with a 1/2 ton. First one was a 22' Nomad with a 1/2 ton 1994 Ford that had the in line 6 Cly. engine. The second was a 25' Sunnybrook with a 1/2 ton 1997 Dodge, 5.2 L V8. Both towed OK but were a little under powered on hills. So yes, you can tow a 5th wheel with a 1/2 ton but it will have to be a small one and within the weight limits of your truck when fully loaded. With the 5th wheels out there today, it may be hard to find one that is that small, but some manufactures still might make them. Do not just go with what a dealer tells you, check the GVWR and GCVWR of your truck and the GVWR weight on the trailers you look at. I see allot of dealers advertising rigs a 1/2 ton towable that are to large and too heavy when loaded.
Rick and Janice Binns
2006 MS 32TK3, Mor/Ryde Pin Box and I.S., Auto Level-Up
2012 Ford F450 6.7 L Diesel, air bags and 25K Reese Signature hitch (factory installed)