They've been around for awhile now, per their website, this is the history of sunnyoutside:
Sunnyoutside was founded as an online literary journal by Publisher David McNamara in Seattle, Washington in November of 2000. In the autumn of 2004, desiring to return to the print medium, plans were made to relaunch sunnyoutside as an independent press in Somerville, Massachusetts. After nearly a year of planning and preparations, our first sale was made on May 5, 2005, just preceding McNamara's graduation from Emerson College's Certificate in Publishing graduate program. In August 2007 the press relocated to Buffalo, New York.
I don't remember when I first heard of this press, but know I was pretty blown away by the fantastic looking books, chapbooks and other items they had on display at AWP 2009 in Chicago. They were sharing a table with Keyhole right next to the Dzanc tables and I couldn't help but wander over and browse through the various items.
While possibly being known best for their incredible looking chapbooks, sunnyoutside has published trade paperbacks as well. Perhaps the best explanation for why their books all look so damn good can be found from the company's mission statement:
Sunnyoutside strives to publish works of the highest quality and present them in a manner that enhances the reader's experience. Our aim is to approach the production of our work the same way a poet approaches the poem—everything has a purpose.
Do yourself a favor and wander around their website and order an item or two.