I needed to make a Pikachu doll for this very reason. I couldn't find stuffed animals that were high quality. What I did find were some great paper craft models and patterns. I constructed the paper model and used it as a prototype for my fabric Pikachu, modifying the pattern to make it work with stretchy fabric that had to be stuffed and sewn together.
This project took about a week and I'm very happy with the result.
The tail was a particularly big challenge. Pikachu's tail is rigid in the game and cartoon and fabric is anything but rigid. What I ended up doing was creating a wire frame and sandwiching it between a ton of fabric interfacing so that the tail would still be somewhat soft.
Mudkip is next.










































Norma
I encourage you to try it. One thing you'll notice right away is the papercraft patterns are usually way too complicated (I think it's because they take computer models and run them through some software to get the patterns), and that fabric lets you get away with much simpler patterns.
Another trick I recently learned when I started making shoes is that if you have an existing toy or whatever you can wrap it in tape, cut the tape off and flatten it and you have a pattern.
Another touch I added was sewing in some fingers. Sorry I didn't take more pictures I wish you luck with your future projects!