I've posted on the other one, but may as well answer here too.
I think there's both good points - shows you're flexible, shows you're determined to work in the area, and bad points - maybe you might look less focused on one project, perhaps less likely to accept an offer. On the whole, I wouldn't let on that you've applied for vastly differing projects, but if they're similar then I can't see a problem. I have in the past and it didn't do me any harm.
Keep us posted!