I know that Cleary puts an odd span on things. I'm fairly certain that they put trusses on a 5' span. Not sure about the walls.
If it were me, I'd kick up a few more bucks, and have them put the trusses on at least 4', and no more than 8' on the post. 5' and 10' is some really ******* settings. I know that a lot of the companies will put the 2x4 strapping across the top of the rafters for the metal, but then if you want to finish it off, you will have to add strapping underneath. That is a lot of strapping for a 5' span, or at least it is in my mind.
One thing to remember....this is YOUR building. You want it to last. Specify what you want before signing anything. It will cost you more, but it will be worth it in the long run.
I take that all back as I just remembered....Cleary puts the rafters and post at a 10' span. A coworker had a 30x40 put up, and Cleary put in the laminated post, the rafters ran across the 30' way, but he only had 5 rafters in the 40' length. So the poles were at 10' apart. I remember it because I am used to 2' spacing, and Cleary had things on 10' spacing, both rafters and poles. They did do a shitload of strapping on the roof, but they were 2x4's laid on the flat.
I was not very impressed by their building at all.