How to finance 7 more duplexes?

[Toben B.]

I have 4 duplexes and I want to buy 7 more on the same street that I have 2 already. 

Total purchase price will be around $500K.

What kind of bank loan can I get for this?

I already have 6 loans in my name and I think fannie mae is limited to 10 personal loans.

Can I finance 4 more at the same time if I get the owner to carry 3 back for me?

Thanks,

Toben