Right now on eBay
Michael Turner
Ashcans and Sketchbooks
2005-2008: Aspen MLT (founded by Michael Layne Turner)

2005: San Diego Comic Con (SDCC) & Wizard World Chicago (WWC):
SDCC
Fathom

SDCC
Soulfire

WWC
Soulfire

WWC
Soulfire

 
2006: San Diego Comic Con (SDCC) & Wizard World Chicago (WWC):
SDCC
Supergirl

SDCC
W. Woman

WWC
Catwoman

WWC
Poison Ivy

 
2007: San Diego Comic Con (SDCC) & Wizard World Chicago (WWC):
SDCC
Batman

SDCC
Vixen

WWC
W. Queen

WWC
Wolverine

 
2007: Canadan National Comic Book Expo (Expo) &
2008: New York Comic Con (NYCC):
Expo
Black Cat

Expo
Spider-Man

NYCC
Batman

NYCC
Spider-Man

 
These are sketchbook / ashcan comics produced specifically for a number of comic cons between 2005 and 2008, showcasing the artwork of Michael Turner.
Each issue was limited to between 250 and 750 individually numbered copies available to the public, however, a few additional copies are known to exist and these are either marked "AP" (Artist's Proof) in place of the number or have no number noted.
The last set was produced for the New York Comic Con in April 2008. At the time, Turner regretted not being able to attend the convention as he focused on his health, recovering from his cancer treatments, however, he sadly passed away two months later.
In late 2016, very few of these had been CGC graded with under 10 copies in the census for each issue.
Prices can vary on these with only a few recent sales.