Having also recently investigated in depth suitable airframes and all other options such as the New Zealand rebuilds (...newbuilds) - the options are limited and costly unless you get a half decent airframe of which I believe all bar 1 are in the hands of museums/collections and even then it is an expensive but do-able project
I have to say my personal concern is that although the above project seems well intended - to be looking for donations monetary or otherwise without (as far as I can see from the website) identifying an aircraft and/or path it is intended to take - seems a bit premature!?