Check out this great application similar to ZBrush or Mudbox for sculpting (I know...it's not the same.) It has dynamic increase of mesh density so that you can continue to add in areas without having to go back and modify the base mesh. It has some great texturing options such as exporting to Photoshop and reimporting the painted geometry. You can paint textures and create bump maps as well. It's pretty cool.http://www.sculptris.com/
Here's an overview video here: http://www.youtube.com/watch?v=6DNRg6pdNeE
I haven't tested it thoroughly, but it seems to export to Octane properly. It looks to be a great addition to any modelers toolbox.
The author is trying to see how a donation system would work instead of charging for it. So if you like it, please throw a couple of bucks (or more) his way.