One way is to use other people's money as was suggested by Arlan, but if you're adverse to doing that (as I am at this stage), you could refinance your townhouse properties and cash out the portion that you used for a downpayment (the HELOC portion) then you can use that money for your next down payment.  

I was talking to someone and they mentioned taking adverse possession.

What was the reason given for the adverse action on your HELOC app? 

@Jake Kozul Find the owner and strike   a deal, BEFORE you pay their taxes.There is another more complicated procedure called ADVERSE POSSESSION, however in Michigan it takes 15 YEARS, and has strict requirements.

Adverse possession means adversely possessing.

This building may have some prior claims that arose that now show up in the CLUE report; that affects rates adversely.

Buying someone's interest and then tacking on to someone's notorious and open use and then gaining title via adverse possession/quiet title?

No shortage of opinions here.I once posted on the the topic of missing owner, vacant and abandoned "orphan" houses with the expectation that a vigorous discussion about adverse possession would ensue, a topic for which I have a high level of experience.

Realtors shy away from crazy stuff that they don't get paid for or that could harm their client, they are not all adverse to investors, most make tons with investors!

@Amnaya A.Your agent has adverse economic interests when dealing with you.