Okay some constructive critism here....
You may want to google some bean bags to get an idea on how there more or less shapped.... Then think out your texture a weeee bit more and I think with a beanbag its going to be more about the shadding effects then anything else...
Personally I can see why people think its a rock or bolder...
But hey your trying and that is what counts...
Don't let the critism get to you it just helps point out flaws that are in a model and some of the guys here are like super good so its alot of competition to go up against in here...
Have you downloaded your CLiPs today.