There are some really strong Gas HD trucks now. These things will flat smoke a Diesel of not that long ago. Yes...the MPG isn't that great but heck, it's a truck for crying out loud!
IMHO if you can keep the trailer light enough...say 10-12k lbs loaded then the right Gas Combo would work well. Get much north of 10k and a Diesel really starts to shine. I also think that a Dually would be the right truck once you get much north of 12k but that's JMHO.
IMHO...if I were in your shoes I'd look at some of the Jayco HT and the Couger XLight trailers as a starting point. These fivers are 7-8 ish k lbs dry which is well in the wheelhouse of a short bed SRW truck (gas or diesel) in a 250/2500 or 350/3500 series truck.
Thanks and good luck.
Jeremiah