I've got literally thousands of signed booked and I'm always interested in expanding my collection too. Let me know if there's anything/anyone you're looking for and I'll see what I have.
The Detroit area is such a depressed market almost anything can be had for a buck or so and I'm always at conventions for easy enough to pick up signatures.
Shoot me a note if you have anything signed to sell also.
Also, I'm not sure how often or how many people use the marketplace feature versus the more conventional ebay/craigslist venues.
It just seems odd to me that of the tons of issues I have in the marketplace, I'm only been contacted once about selling an issue then no follow-up on my repsonse, which I'd be shocked, nay mortified if he thought my price was too high.