Gents (and Katy? ;-) )
We at PMDG have made a very earnest effort to address all such external hardware requests. I am working actively with Andrew Mc Lean to get our aircraft working with the MCP747, as Andrew has been kind enough to send me a sample of his hardware, for development & testing purposes.
We have also been contacted by Mike Altman regarding the PFC hardware, however everytime I replied to him, my reply went ignored or unanswered (don't know why - I know he receives the emails, as I never get any bounce-back about it).
The Go-Flight hardware developers, on the other hand, have never attempted to contact PMDG or me personally, so I have no clue about that.
I can ONLY provide responsible and forthcoming help and support to those hardware vendors who are willing to provide me with test hardware to work with - it's unfortunate, but without working hardware, I cannot program something that "might" or "might not" work correctly.
Hope that everyone understands PMDG's position on this one! :-)
Best regards,