Hi Jim, I towed a 1500kg caravan for a couple of years with an RX400h. I had no problems whatsoever towing, it was very stable tug in every respect. Just a couple of things to be aware of: Front tyres will wear out quite quickly (depending on how many miles you do of course) I was getting through a set of front tyres in about a year. Secondly you will consume a fair ammount of petrol, I was getting 18 MPG all the time towing no matter how light my right foot was! I subsequently traded it for a Mercedes ML but wish I had kept the Lexus.
Hope this helps
Brian