I bought a goose neck trailer last year, a similar one would fit your needs. It is a 25 foot flatbed with a 5 foot dove tail and three fold down ramps (commonly called a 25 and 5). The trailer has two 10,000 pound axles for a 20,000 gross weight. The trailer is 6000 empty so that would give you a net load of 14,000 pounds. If height is a concern (legal height in IL is 13.5 feet) a low boy version is available but will only lower the deck by about 6 inches and cost you a bit more. The standard height trailer would be in the $6500 range.
I am in south central Illinois and if you are looking for a good buy on a trailer, people go to Sikeston, MO (about 120 miles south of St. Louis on I 55) where there are several manufacturers. I paid $6500 for my trailer and similar one at a local dealer was over $10,000. They will do custom orders too, we had a few more supports added to ours and upgraded to the LED lights.