Rewards for smaller donations sound great! I personally only donate when I really, reeeeally love the gotq, because 20fc are a lot of money. With 5fc or 10fc gfts, I might not be quite as picky and donate more regularily.
As for what those rewards should be ... tricky question

-I don't think giving out past items is a very good idea, since that could decrease their value quite a lot and and surely upset some users.
-The gold-silver-bronze recolor idea is very cute in theory, but I agree that the silver/bronze items might not be as popular because browns and greys aren't very popular colors in general.
-Picking a favorite color for the King or Walla is a nice idea!
-additional idea: something like a donation fairy? Have a set of items in several recolors, and if you donate at all, you get one random item a month, and if you donate beyond a certain threshold, you get a second random item? Or tie them to certain amounts of FC in the first place, so x amount of FC gets you one random item.
Or make it a donation nymph or something, so there's no rivalry with the fairies xD
Possible problem (as seen with the wild knuffel items): when new items are added, the old ones become a bit of a nuisance because there are already quite a few of them in the pool. But maybe that would make them more accesible after a while for users that can't donate, which would also be nice ... I dunno. Just an idea I had!
As for giving out a gift for very high donations, like 40FC ... I don't think that's a very good idea, honestly.
In past discussions about site activity, one major complaint and source of frustration I remember was "the things I want are too hard to get". So adding items that are behind an even higher paywall sounds counterproductive.
Not to mention, with kofk being so small, how many potential donors are there even that could afford donating for a 40 fc gift? If Firn had to come up with an extra pretty donation gift for extremely high donations, and only 2 or 3 people got it ... that doesn't sound like a very good use of Firn's time, creating items that only a tiny amount of people will posess. And other users might get frustrated, because the item is basically impossible to get for them...
I think getting some users that don't donate yet to donate a little is a better plan of action than trying to get the people who already donate a lot to donate even more. Just my two cents however
