I have seen an older 1500 dodge Hemi towing a 30 plus foot fifth wheel trailer. I asked the driver about the combination and he said it was just "fine." Sorry, but that couldn't have been a safe combination to be around.
Don't over do your tow vehicle. It's got plenty of horses to pull the 10,000 trailer, but so many other factor come into play--like tire capacity, brakes, trans, springs, etc. By the time you address these issues, you might as well step up to a 2500.
I LOVE my 6.4 Hemi, it gets good mileage and handles our 10,300 fifth wheel like a dream. Come on over to the other side....
Do not believe sales people. I often wonder about the liabilities if one crashed and hurt others while driving a rig not complying with the manufacture requirements.