Maybe later today, if work wasn't such a bitch again...

Vephriel is right. Models that are transparent will always look odd as they take some of the background color with them. Unfortunately, web graphics do not allow any semi-transparency. So Arcturis will never be an option, I'm sorry.
This is what Arcturis would look like on black background. If I used a white background, he'd be invisible.
I did some work on a normal bear but it really didn't turn out that good.
So, Arcturis is not an option, I'm afraid.
Edit: I just had an idea I have to try tonight. Maybe Arcturis will be an option but no promises yet.