Here's Squirtle, in a realistic-ish concept style. Again, needs to be refined, but meh. Also, I made his tail fluffy because it's apparently meant to be a Squirrel's tail (hence the 'squir' in squirtle, although I always thought that had something to do with 'squirting' water).
I tried to make look like a river turtle, rather than any other species. Now he just looks amphibious.
Photoshop Elements 3.0/Wacom Graphire 4
Time: About 3 and a half hours
Pokemon (C) Nintendo
Art (C) Me