A next level could be headers for site, and logo design.
I don't recommend that. Headers and logo design can't be "explained" in tutorials. That's graphic design and you can't study graphic design from tutorials. There are schools for that.
You can make tutorial about fancy web 2.0 effects that you could use when designing headers and logos but that's all. You'll need much more then tutorial or two if you're going to be a logo designer.
My advice to you, and to anybody who makes tutorials, is to stick to technical stuff, like creating effects, using tools correctly ...
You might also try to help members with Colour in design and websites. Beginners often struggle with this. This could include colour of text on different colour backgrounds, and tghe 'messages' sent by different colours. These may vary acrss cultures.
Yes, I do that by posting on "Review my site" section all the time. I encourage people to start threads about this. That way everybody else can see it and maybe learn something useful.
EDIT
I saw your tutorial about Pen Tool and I'm a bit disappointed. When a complete beginner starts using pen tool he/she will certainly make a lot of mistakes. I think that in your third tutorial you MUST explain how to edit already created lines and shapes. This is not an issue just for beginners. People (including me) always make a basic shape and then tweak it to be perfect. Creating perfect shapes and lines without tweaking needs a lot of skill and experience.
