The thing about using a broad term like “speculative fiction” is that it can be a bit tricky figuring out what does or does not fall under that umbrella (especially with something more poetry than prose)… but I’m pretty sure that a book of blurbs about itself (the book of blurbs) qualifies, especially with contributions from familiar spec fic names such as Dean Alfar, Mia Tijam, Adam David, Andrew Drilon, Josel Nicolas, Khavn, and Budjette Tan. Curator Angelo Suarez has thrown up a PDF sampler which you can find here, and I’ll let him explain the project in his own words:
This book was assembled in 2009 as something that was titled “The Blurb Project”— admittedly an unimaginatively unimaginative tentative name—intended for release w/in the same year. The procedure: Ask writers to blurb for a book whose content would solely be the blurbs to be collected from them, a critico-creative exercise in closed-circuit self-reference that could function as a collaborative epic poem of modular components. The material gathered was hence largely speculative: the book would talk about itself even before the book was complete, the collaborators either working blindly or else w/ what few blurbs were already available for their use.