Gooseneck trailers are probably not practical for lighter duty trucks. They put a lot more of their weight on the truck itself (typically in the range of 10% for bumper pull, 25% for goosenecks) and can pretty easily exceed the payload limit.
For example, a 2007 Chevy Silverado 1500 Extended Cab with 6.0L V8 engine is rated to tow 7500 lbs, but has a payload capacity of 1250 lb (according to Edmunds.com
). If you wanted to pull a 3000-lb gooseneck trailer carrying a single 1200 lb horse, you're up to 4200 lbs. 25% of that weight- the weight that will be put on the truck- is 1050 pounds, leaving your truck with 200 lbs of payload capacity left. That 200 lbs needs to include YOU and anything else you're bringing with you in the truck.
Gooseneck trailers weigh more than bumper pulls anyway (because of the extra material needed to create the gooseneck) so while you might be able to find an aluminum 2-horse bumper-pull trailer that weighs 2000 lbs, you'd probably be looking at 2500-3000 lbs for a similar gooseneck model. (ETA- make that more like 3300+ lbs... here's Featherlite's gooseneck trailer weights: http://www.fthr.com/~/media/Featherl...ights-1012.pdf