We are a newer company in the eyes of the Expo forum crowd, so here are couple items about us. First we come from 30 years of Family aviation biz, so failure is not a option.
http://www.4wdmechanix.com/Video-Review-Sierra-4x4-Trailers.html
http://www.fourwheeler.com/featuredvehicles/129_1110_sierra_4x4_off_road_trailer/index.html
http://www.sierra4x4trailers.com/
As far as leaf spring vs. Air bag..we offer both, but most of our customers prefer the soft ride leaf springs that is proven and maintenance free. We offer the independent air bag suspension as a option.
We also can build any trailer you want for a fair price, 90% of the trailers are manufactured and assembled in house. So this mean you start with a blank canvas, and you are the artist and and we are your brush and paint.
Our trailers like AT's come with Title's and VIN's approved by the DMV.
All of Sierra 4x4 Trailers are in CAD programs. So if your trailer is custom and you need parts 10 years from now, we keep the drawing's in a file so that is not a issue.
*Added Info: We are bit overwhelmed with orders right now so we apologize if we do not return call's or E-mails that day. We are also working hard to speed up the build time on our trailers. Plus we have been working on new layouts on our trailers to make it possible to have a customer order a trailer, and it would be ready for delivery in 2 weeks. This new layout is not a go as of right now, and will take some time to stream line this plan.*