We use a 10K 6" riser from Roadmaster. It's available through e trailer for about $100.00.
http://www.etrailer.com/Accessories-and-Parts/Roadmaster/RM-048-6.htmlThey have several others depending on your needs.
http://www.etrailer.com/s.aspx?qry=6+inch+dropAs a side note the Jeep we were towing was rear ended when we were going through Illinois a couple years ago. We were doing the speed limit of 65 when we were hit from behind by a kid going about 75 while texting. The towbar, baseplates, and drop hitch were destroyed. The impact was hard enough to bend the drop hitch.
Fortunately there was no damage to the motorhome. However I believe if we had used the lighter drop hitch it would have collapsed and the Jeep would have hit the rear of the motorhome.
