You can really poor a bunch of money into your rigs, I decided to try and find an equal point (toys=rig). I am full time 20 year old college student, with a mortgage, truck payment, and school so I went pretty cheap. I found a 2004 Carson Titan used in California, I paid $8000 with a Honda generator, I have fit 4 banshee's and an LT80 standing up one banshee. This is all in an 18ft trailer. My suggestion is buy a used Carson atleast 20ft. When you buy a new trailer the moment you drive off the lot you will be taking a huge loss, let someone else take the loss and buy used. If you end up buying a new trailer, I would go with Weekend Warrior, those are well built trailers, and hold their value better then most other trailers.
Kevin