single origin options

So, at Bradbury's we have two espresso grinders... in one we have Kickapoo's espresso crema, which is our default espresso for drinks with more milk than a few ounces. In the other grinder we have been pulling various single origin shots roasted by Kickapoo. However, it seems like it would be fun to try serving espresso (in general focusing on single origin shots) from some other roasters - this week we ordered 10lbs of black cat espresso from Intelligentsia, and we now have an account with them so we can begin ordering some other coffees as well. We also have some samples from Verve that we are going to play around with at the beginning of this week, and we may start ordering from them soon. My goal is to be able to find about eight different roasters who are willing to sell to 10lbs of coffee to us every two months or so, and rotate through these on a two month cycle. That being said, I'm curious if anyone has any input about roasters, and specifically coffees that you have tried as espresso, that you are excited about (if you have any idea about what temp/extraction time/etc. that would be really helpful). I've been contacting various roasters and some are open to this idea, while others are not willing to sell this small of an amount of coffee to a cafe. Thanks for any input you may have! (fyi, stumptown and blue bottle are not willing to sell in this quantity...)