Hum... this is NOT done yet, but I thought I'd throw what I have so far your way before continuing.
Started getting WIParanoia halfway through and wanted to get your word on it before continuing any further. It's the eyes; I was shooting for stressed/off his rocker with the lines under the eyes, but I can't tell if I nailed that alright or just made him look old (admittedly I blew the pic up x2 to zoom in because it's more of a problem when smaller). Also, pardon the crappy anti-aliasing, I'm used to working in a lower res and can fix/touch that up later. I feel like I shouldn't be anti-aliasing by hand, like there's something out there I'm not aware of that speeds the process up nicely...
Anyhow, enough of my paranoid ranting. What're your thoughts thus far? I plan to add ruffled hair, and naturally his other ear will be full length. A deranged smile will help too, I think. And blood, I'm gonna assume you'll want some of that mixed in his fur, given the refs.