At some stage I'll open up the floor to mesh/skin requests, but will forewarn people that I don't much like the Xmen, Ultimates or New Avengers, so they are for me VERY low priority meshes.
Which means ah'm screwed, as I'm an X-Men fanatick. 
(This would be the point where I ask you if the exporter allows the creation of sub-meshes, such as ones used in MUA for weapons, as Hawkeye obviously draws his arrows from his quiver as boltons - they become separate models only once shot; he also looks like he tries to put the bow away after each shot, but it's glued to his hand
)
And, on a seemingly unrelated note... Why isn't Hawkeye's head moving with the rest of the anims like it did with the (native) stand-in models?
No, nobody's screwed, they just aren't my top priority. If people request them (and I 'm guessing they will), I'll make them, I just wont tend to make them of my own volition the way I would Avengers characters. And call me elitist, but anyone contributing to the Modding/meshing/skinning/programming scene gets requests done as a matter of course (provided I actually
can make it of course). Got to keep people sweet.
RE the bolt-ons, bows, guns knives built in to the mesh, and being able to put them away. Good news/bad news. Yes you can have seperate bits is the good news, how you set them up to disappear during the animations? I don't know is the bad news.
Remember that there is zero documentation for how to do anything in this game, and I consider it pretty much dumb luck that I managed to figure out the export settings at all. When I look at my meshes in a hex editor to look at the structure, they look to me more like the XML2 meshes than the MUA ones, at first glance.
It's one of those "to be figured out" things, and I'm still very much on the basics at the moment.
As for the Hawkeye head, well, in meshing when you physique a mesh you assign all the vertexes in a given area to a bone in the biped skeleton. When I assinged the vertexes in his head to the head bip, his head got stretched four foot upwards, so I assigned them to his neck bip instead. It's another thing I need to figure out, or it may just be something that we'll have to live with if I can't figure it out. Hopefully other meshers will start to make stuff and crack this and other problems if I can't.