This sounds great. Can´t wait to see the finished product. Personally I´m not that interested in a HDMI Gamecube mod anymore, since Nintendont homebrew on Wii U came a long way. Together with the official Gamecube adapter, widescreen hacks, forced 480p and of course the HDMI out of the Wii U it pres...
Please supermario3, just read.
Answers to all your questions are in this thread.
Marschallh will sell the adapter to installers and resellers, whom will then sell premodded N64s or mod your N64.
That has been stated numerous times in this thread and also on the project page.