And lo, the Visual Studio build tool did proclaim to the masses, “Interop.Photoshop8.dll” and “Interop.Photoshop9.dll” both declare “ps.Application”. And there was much wailing and gnashing of teeth, for another clever approach had failed.
(seriously, if anyone knows how to get multiple interop DLLs for a single interface to play together in VS.net, or alternatively, why an older interop DLL would not be able to invoke a newer version of the same interface in COM, please please please let me know)
Edit(2:09AM): hurr, if you build the object library manually with a different namespace, you can use both. Of course, now this opens up multiple namespaces for a single set of actions, but that does reduce it to a design issue rather than a “bang the rocks together” issue..