I am able to get the parks with 10% down (80% bank financing and 10% seller financing), but I still worry that I may be overpaying.

2) A local, small town bank/credit union?

Anyone in the Milwaukee, WI area know of a bank or credit union that will do a HELOC on a rental property (not owner-occupied)? 

Bank financing takes too long.

I was short on cash, didn’t want to do the bank thing, and it was the only way the seller would sell.  

Most lenders require your personal name to get loan, especially Banks. 

Once they are foreclosed the bank owns them, and it is trickier to get the right to wholesale- they want the most they can get and they have formal processes to go through.

ask for the last three years of Schedule Es and bank statements.

I'm going to cold call 100+ landlords in the area and organize an informal meet-up at the local tavern so I can meet a couple dozen landlords and let them know I'm looking to buy some multifamily properties..The downside of this idea is having to syndicate the money between what I can put down and what the local bank will finance.

The main benefit is you don't have to deal with bank underwriting/approval and typically need less than 20% down.