Title says it all, I'm looking for a drum machine for live performances and I'm not sure what exactly I should go to.
No, I'm not getting a real drummer, this is a specific project for which I want a drum machine.
No, I'm not getting a computer based one, simply because I can't justify buying a laptop computer just for that as it would end up being hella expensive. I'd like a hardware based one, such as an Alesis SR18, which I've been considering.

The key feature I'd like is that I want to be able to let the drum beat play and change it with a footswitch. However, I don't know how easy it would be to find; I actually can't seem to find it. I guess a sequencer would do as well; I can always program the whole thing, but I like the flexibility of having riffs I can change anytime to change structures on the fly.
I would like to be able to control it by footswitch because, well, I'm playing guitar at the same time.

As for what I'd do with it, it would be more or less something similar to The Kills.

Thanks guys =) hope I get some ideas, because I've been having a hard time with it.

As for the budget, I'd like to keep it relatively low, around 300 bucks maybe.
I have a Boss DR770 and it only allows a single pattern selection assigned to a FS.
I got it on CL for $100. Also got a DR5 for $60. I like the DR5 built in patterns but the 770 is more powerful for programming.