Thanks for the quick response!
I hadn't thought of trying the cayenne powder. I'll try picking some up next time I'm out.
And I'll check out some mexican stores too, that hadn't even crossed my mind.
I just recently became interested in making hot sauce (just for myself), because I love sauce and it seems fun.
I have almost no cooking experience, so this is all brand new to me.
I'm not (yet) interested in growing my own peppers, so I am just sticking with stuff I can buy in the supermarket...