Bad news first: the Savage Mushroom Kingdom netbook I mentioned a couple years ago has gone dark. The good news is the reason for this, namely that the author - Jeremy Puckett of Blackwing Productions - has secured the necessary permissions to make his Land of Terra an official Savage Setting. There is, I understand, a Kickstarter planned for later this year, but in the meanwhile the rough draft of the Heroes of Terra Player's Guide - very similar to the old netbook - is now on DriveThru. It's even the Deal of the Day for the next few hours, but I'd say it's worth buying even at full price (a mere $5).
Also available are two short adventures, The Plumber's Dilemma and Down the Tubes, both priced as PWYW. They're well worth a look to see how the occasionally goofy Mushroom Kingdom setting elements - the second one alludes to Karting! - get translated. With all the elements thus presented, the full setting book is shaping up to be quite good indeed.