Wow. How did I ever miss this? I just installed to my K5, and it's working great. I especially love the font size and margin hacks! I was always bugged at not being able to choose an in-between font size, the default was usually too small or too big. This plus smaller margins is brilliant, thank you! (I did have to try a bunch of different variations to get the in-between fonts to work).
My one question: Current firmware is 5.1.2 Even though I've been on wi-fi a lot the last six months, it's never updated. Can I assume my Kindle is immune to update attempts for some reason? I do have an early jailbreak and special offers hack installed (shhh), is that acting as a firewall?