I once saw a cookbook step-by-step guide for using xotcl with aolserver. The posting might have been here or on the aolserver mailing list. Try writing Neophytos, as I know he has used xotcl with aolserver.
As far as compiling [incr tcl] with aolserver, I don't know. I haven't looked at it. It probably wouldn't be too difficult to turn [incr tcl] into an aolserver module, but somebody would need to look at to make sure that it is designed for multi-threaded operation.