How would you structure this plex deal?

[Kelly Maestri]

If you didn't have 25% cash to put down on this deal, how might you structure it? 

Here's some info....

Duplex in CO

$610K asking price 

$575K is amount the investor/owner will accept 

$0 loans on the property (as far as I can tell from RealtyTrac); owner is investor/attorney

$57K is amount I have for down. BUT, I will receive a cash influx that would at minimum cover a 25% down within 6 months.  

I cannot move into this property (I live in CA) so no FHA 3.5% down or 10% down for 2nd home loan because its a duplex.

Property is immaculate so no concessions for condition.

Is there a world where this seller might hold a 2nd as a gap loan of sorts? Defer cap gains?  

Thank you in advance for your ideas or feedback (e.g. know when to fold 'em).