Connect 2 SMALL Perpendicular PCBs - Need your creativity!
Consider using a flex circuit

FH12A-12S-0.5SH(55) with 12 pins is one I'm using now. This series has 0.5mm pitch.. 10 pins is less than 10mm long even with the end hinges. 

You need to specify the FPC with a stiffener that meets the connector thickness requirement and to make the shape tolerances compatible, other than that it's pretty painless. 

The lever cover makes connecting a snap. 



There are vertical types too.