George -
I'm not sure why such a blanket condemnation of tongue mounting. I can think of a couple things that might need to be considered, but might be overcome.
1. I, personally, might have second thoughts about running a (hot) generator snuggled up against the propane tanks - not to mention the rubber propane hoses and the propane regulator.
2. A generator on the tongue puts essentially all of its weight on the rear axle of the tow vehicle. Can your tow vehicle accomodate this extra weight? Be sure you have a weight-distributing hitch, and that you crank it up accordingly. And be sure the generator mounting method doesn't make access to the spring bars too difficult.
3. You will want a REALLY good cover for the generator, of course. That's a grubby location in bad weather.
One of our members did, in fact, put a generator on the tongue - a very nice installation by Custom RV in Anaheim. He had to move the propane bottles, but apparently it worked. Unfortunately, the pictures were lost in the last forum upgrade, but the thread is still there, at
http://www.trailmanorowners.com/foru...ead.php?t=1501
He hasn't posted in a couple years, but you could email him or send him a PM.
For permanent mounting, I don't think there are any really good options. You can't put that amount of weight on the TM's back bumper - especially if you are talking about a pair of generators. I've seen some mounted on the front bumper of the tow vehicle, which seems to me to be a great location. But that's not common. Many people seem to opt for keeping them portable, and carrying them in the tow vehicle.
Bill