IDW does a lot of variant covers for their My Little Pony books. They did sketch covers and, something I haven't seen before but really dig, sketch back covers. They print them on something that's effectively bristol board, takes pencil and ink really well, and people can commission us to draw on them. Coming out of last week's My Little Pony event at Beach Ball Comics, I got a series of four covers, two fronts and two backs to draw. I'm pretty happy with how these came out. I do have some blank covers in my box of comps from my Twilight Sparkle issue, so if you're interested, drop me a line and we can talk price.
Either way, here are the covers I did. Click and embiggen!