Thanks for the input Rockm and Chris. These elms grow all over where I live. It always seems to be the case - whatever is most abundant in my area is poor bonsai material. I'll keep searching. I have a lot of eastern red cedars in my area too but don't want to deal with cedar apple rust.
I tried looking for Dave's email to ask him how his Siberian elms is coming along. I was not able to find his e-mail address.
Dave V