I haven't tried this, but shouldn't DCOM, where marshalling is by RPC, should still work, shouldn't it?

>>Hmm.... in .Net 4.0, COM can be accessed by using Dynamic. I wonder if a 32-bit COM dll could be accessed that way, running on 64 bit? I think I'll give it a try in a couple of days, just to see what happens. Unless you already know, which is a distinct possibility. <s>
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>A 32-bit COM server is registered in 32-bit registry. A 64-bit application doesn't access it.