Just thought I'd post my progress so far on my centaur piece. For once I'm having more fun working on the background than the characters/creatures. I'm going to have stop myself from working on the bg now though otherwise I'll never get the actual centaurs done.
I had drawn and started to paint them once, but they really don't fit with the image, so I think it's going to be a case of completely planning them out. Although before I start on them I think I'll do the backgrounds for all my other pieces whilst I'm having fun with them. I usually struggle with putting character's in environments so I may as well take advantage of my current enthusiasm for them.
Really rough sketch that I started with (this is actually a really old piece which I had thrown to one side thinking I'd never use again. Good job I kept it).

And what I believe to be the final version of the background for this piece.

Whilst I'm at it I thought I'd throw in what the centaurs were going to look like, thus being able to explain better why I believe they don't fit. As you can see, they're just "there". I want them to interact more with their environment and make it clearer as to what they are actually doing (hunting). As I said before, I'm going to come back to these guys later on. Partially because I work quicker on creatures than on backgrounds, and mainly because I'm getting way too frustrated with them.

And finally, last picture, I promise. I just thought it would be nice to show the tones and values in the image. I'm usually quite fearful with using bolder shades, shadows and highlights, but I think I'm getting there.