If you use traits you could take the heirloom Weapon trait and take prof with scimitar,
Human Rogue/Fighter
Rogue 1-Weapon Finesse, Dodge
Fighter 1- Dervish Dance
Rogue 2 - 1 Rogue Talent, 1 Feat
Fighter 2 - Feat
Rogue 3 - Feat
Continue Progression in either class as desired. Try and match odd levels of Rogue or Fighter with you odd Character levels so you get either a feat or rogue talent at each level.
