Rotary Pulse switches...

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First and foremost, check this site and get FSUIPC. Its the holy grail of flight sim interfacing.

http://www.schiratti.com/dowson.html

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I know the feeling! I've burned over 400 gals myself testing different switch setups.
Anyone know which is the Taxi command and Beacon?

This might get you started:
http://www.simpits.org/engineering/KeyEmu/Key_Emu.html

And I have seen a web site somewhere that a person built his entire MCP from a keyboard, I will look for that link.