not only i agree with you Rick giving AppGameKit v1 is good no matter how you look at it, more users = more games = more publishing = more cool stuff ...
and about the price 50 E and up is fine
however ... i would put 55 E as it is already
and 65 E for getting the same as the 55 E donation plus! AppGameKit v1
buying it for additional 10 E.
and also i would encourage you that everyone who backed low donation and is not an AppGameKit v1 user.. give them a disscount if they want to purchase AppGameKit v1 before the release of v2.
Edit: the best option is this:
if the pledge is higher or equal to the current price of AppGameKit v1 , let them have it.
if its low then the current price of AppGameKit v1 , the price should be minus their pledge amount.
simple and efficient so no body here on the forum feels weird ...
Great idea Rick.