We have a 2005 Tropical 370LX with the 350 Cat.
Very nice coach well. Well built. Good quality throughout. Not sure if there were changes between 2005 and 2007 on lay-out, etc. We love ours. We are second owners and have had it for just over a year. It has 32K miles no issues. We spent every weekend in it this summer beginning with 4th of July and we just brought it down from the mountains yesterday.
I have three friends that also have National products and they are all very happy as well.
Palm Springs, CA - 2005 National Tropi Cal 370LX on a Freightliner, Cat 350 power. Towing a Rinker R1 - Lake Havasu Bound!!