I am actually leaning to zelcova for your tree pat, yours i am quite positive is not a chinese elm, the bark is just way to light. Matt yours is definately NOT! a corky bark elm, sorry champ corky bark does imply a corky bark and even a tree of only a few years old should have some form of plating and corky-ness. also with yours the bark looks very similar to one I have that I havent been able to identify 100% the small leaves and the texture of the bark with that semi dehydrated look (even though it isnt) i am a little iffish about what it is, I dont think it is zelcova, will soon find out as i have a fair few coming up, like i said previously I also think it could possibly be siberian elm, how tight are the internodes on yours matt?
either way guys they are really good trees to work with and you should see some good movement with them if you feed well and they have the room to grow. most elm are notorious to stop thickening once in a pot or confined area, branch development is ok but is best to have in an over sized pot if you want more vigour in branch growth.
keep us posted
taking the top half of trees of since 2005! 
I have been looking through the net of ch. elm and have noticed some difference's in colour, some being a darker grey then yours on the new branchlets, being that the trunks and branches of yours and mattsbeing lighter in grey i tend to lean to zelcova or english. if the trunk starts to go brown and developing a rougher bark then it could also be ch. elm. but like I said its a time thing, the care is the same pretty much so i wouldnt be too stressed 
