I just bought a new 5th Wheel. I have had one before and it came with an old hitch (don't recall the brand but it was nothing special). My new 5th wheel has a GVWR of 12,000 lbs - Dry Hitch of 1625....
We have the Reese 15k slider that was included in our 2003 Laredo 5er purchase. It must have sat in the lawn for a while - our mechanic had to clean it up and lube the heck out of it because it had "frozen" - but it works beautifully now. We don't even need a slide hitch (long bed truck) - but are glad we have it in case our next truck is a regular bed.