You may copy one version in the vs.net 2010 visualizers folder in program files, but other than that, it's not going to work as the ormsupportclasses dlls have the same name.
You may also rename the debuggervisualizers dll, but not the ormsupportclasses dll which is referenced by them.
You could add the ormsupportclasses dll to the gac, but that's not free of charge, as it would mean you have to update that dll when a new one is released.
Well you could do that for v2.6 though, as that one isn't updated that much anymore.