Gatortail trailers has the best deal on new enclosed trailers. They're out of Valdosta Ga I think and offer a factory price to the public.
All I'd look for is 3/4" plywood floors, 3/8" plywood walls with verticals 16 o.c. LED lights, brakes and twin 3500# axles with brakes. Other than that and you'll end up changing it anyhow to customize it to your style and trade, I've had mine for about 9 years and its evolved to my liking no less than once every other year. Plain is key to new. Also I have barn doors and wished I would have gotten a drop down with spring assist.
You really want to avoid the osb walls as a lot of them don't use quality material like Advantech and do it to cheapen the price. Those particular walls wont hold any fasteners for hanging stuff etc.