Lost Dutchman Coffee sells green coffee beans in blends suitable for espresso as well as single origin.
After roasting at least 40lbs of LD coffee over most of a year, I have come up with a great roast 'Full City' roast profile for both of their espresso blends (Gold Nugget and Jacob's Dynamite) that has balanced acidity with a nice cocoa flavor. I had more luck with LD coffee than Sweet Maria's blends so far.
Roasting coffee is tricky and even small changes in roasting temperature and timing produces significant changes in the flavor of the coffee, so your results will vary depending on your equipment and technique.
Get yourself a home coffee roaster (I use the Fresh Roast SR500 modded with a thermocouple) and try your hand at coffee roasting! Its lots of fun and you get a fresh cup every time you brew.