Actually, comics can be about whatever they want. They could be about Pokemon, but you don't really have to base them on Pokemon.
However, since there are so many Pokemon comics around here nowadays and almost no comics based on other series (other series comics tend to die out quickly for some reason, only a handful tend to survive through their first month, and even fewer have huge popularity...), it seems like only Pokemon comics are allowed. That is not true in any way, so just go out and make your comic about whatever you want. The possibilities are endless.
The only exception to this rule that I can think of are comics with adult themes like sex and such that are 'fully expressed' in the comic itself (I think just talking about these kinds of things in the comic is fine, but actually trying to draw the action...). But even then, it's common sense to not do that nowadays, especially on a Pokemon forum.
You're not the only one who wants to start a comic but can't find any ideas or have the ideas but can't start one due to other restrictions. I've been thinking about making a hand-drawin comic as well, but I can't really make a comic for the time being, seeing as many other things are keeping me occupied.
All I have to say is this: Good luck with your work.