Most of the properties purchased by PE funds were acquired at the trustees sales and there are no restrictions on the resale.  

Good to excellent credit opens up a whole world of cheaper and better financing.On your comment about your past (and I have a pretty dark one myself), there are no legal restrictions on Real Estate investing that I know of on anyone with legal issues in their past.

Sorry for my long answer to a short question....I'll sign exclusive for the deal realtor brings me only, if we build a relationship of trust I might consider time based, but will never sign one that restricts me from deals from other sources and/or requires me to compensation someone for a deal they had absolutely nothing to do with.

I'm embarking on my first direct marketing campaign.  

What you need is a Fannie Mae direct lender that does not have internal restrictions of 4 loans per borrower.

You might even do an ad campaign soliciting interest should the land transaction be consummated.

I will suggest that you put a sustained direct mail campaign in place to find your own deals vs. reviewing properties that are already for sale.

I also want to start a direct mail campaign, but I'm not sure how to do that yet. 

I would expect an untargeted offer campaign to have even less success than that.Learn how to focus your efforts before you invest any more time / resources.

I have  advantage of knowing area, country and certain restrictions which would not let everybody acquire these lands.