2nd(but primary) duplex with under 20pct down in Chicago

[Chase Schwalbach]

Hello all, 

I'm looking to keep my current home and rent it out in the Chicago market. My current payment is around 700 less than I can rent it out for, and it's in an area that is rapidly growing. 

I'm wanting to move into a new unit with 2-4 other units in the property. In terms of monthly payments, the 700 will cover almost the entire difference, and I'm able to put 10-15% down but would have to wait another year to save the final 40k to get me to 25%, which is apparently common in the area. 

Does anyone have any advice for getting a mortgage without the full 20-25 percent down if it's my 2nd mortgage but I'm moving into it as a primary?