What should my approach be given my situation?

[Noah F.]

I own a single family home free and clear, worth about $350k. I also have about $50k for a down payment. My FICO scores are 750+ and I have no debt of any kind. However, my monthly income is less than $2,000. Traditional lenders have told me I'd be lucky to get a $100k mortgage, which might get me a condo, but really I'd like to start with a duplex. I do have a friend, also with 750+ FICO and no debt, who is willing to co-sign. Our combined income would be about $3,500 a month. What are my options by myself, and with the co-signer? Based on my limited knowledge, I'd guess if I wanted to start with a $250k+ duplex I'd need to cross collateralize? Thanks!