Add in world class infrastructure, freeways, DFW intl airport, central U.S. location, and you get a better understanding of what's truly happening.  

My thoughts were ( and it seems to align with yours) to buy the land, developed it into leasable lots with all utilities and roadways and possibly installed a central pavilion and grass area for the community, then purchase a model manufactured home and up to five for placement.

I don't quite understand your request.My local Wholesalers (these are the websites I use frequently) in my area would not benefit you any unless you are looking to buy in the Central Florida Area.The best resources for deals would be:MLS (depending on Area you want to buy)Agents (Realtors) (depending on Area you want to buy)Brokers (depending on Area you want to buy)Wholesalers (depending on Area you want to buy)Local REI Meetings (depending on Area you want to buy)Friends & Family (depending on Area you want to buy)Bigger Pockets (depending on Area you want to buy)

My banker can no longer approve my loans by the way, they must go to a committee to approve them now, something about passing his authority limit.

Perhaps the most central hub to all of the US. 

"- It is my understanding that any and all services that use ACH/EFT billing (Google Wallet, Paypal, Venmo, Cozy, ...) leaves the landlord at the mercy of the tenant, as the tenant can reverse charges simply by claiming that the ACH debit was not authorized.

I've written fairly extensively about the Sacramento and Central Valley Markets and what kinds of multifamily investments are available there. 

Some brokers need to authorize you for each property but most are very easy about it.Another source would even be Loopnet.

The Condo where I own doesnt like the signs inside, so I put mine out on the street where the condo has no authority, but it gets attention, and causes ppl to drive in to take a look.

There should have been a Tax Certificate in the package that lists all the different collecting authorities