"Mutating the Signature" was an "issue" of the online journal qarrtsiluni that ran just over a year ago, and featured only collaborative writing (including Daniela Elza's and my poem, "silence: a courtyard"). The "issue" has recently been turned into a real, stack-o-dead-trees print issue, which is available for sale. Yay!
I quite enjoyed reading the contributions as they gradually came out online (you can read the online version here), and I think the print version will make for a great read (the authors' notes on the writing process are often as interesting as the works themselves). More details, a sample of a few pages, and ordering information is all here.