Okay, I see two options I like for the Dervish route.
Scout 4/Swashbuckler 3 - BAB +6, Fort +5 Ref +5 Will +2 8 more skillpoints than ranger build
1 Sct 1: Skirmish (1d6), trapfinding, Able Learner, dodge
2 Sws 1: Weapon Finesse
3 Sws 2: Grace +1, Mobility
4 Sws 3: Insightful strike
5 Sct 2: Battle Fortitude +1 (initiative bonus), uncanny dodge
6 Sct 3: Fast Movement +10, Skirmish (1d6, +1 AC), Trackless Step, Weapon Focus (Scimitar)
7 Sct 4: Bonus Feat- Combat Expertise
Ranger 4/ Swashbuckler 3 - BAB +7, Fort +8 Ref +5 Will +2
1 Rng 1: ACF: Arcane Hunter, ACF: Trap Expert, Wild Empathy, Able Learner, Dodge
2 Sws 1: Weapon Finesse
3 Sws 2: Grace +1, Mobility
4 Sws 3: Insightful strike
5 Rng 2: Combat Style - Two Weapon Fighting
6 Rng 3: Endurance, Weapon Focus (Scimitar)
7 Rng 4: ACF: Champion of the Wild (Combat Expertise), ACF Distracting Attack
Going scout gives some good battle bonuses like faster movement, higher AC and higher initiative while ranger gives higher BAB and a head start on TWF. I think that's as good as I could get for a dervish build that still can function as the party's detrapper.
I've strayed quite a bit from my initial concept of combining a high int for rogue with insightful strike and running from there. I'd like to think about some options other than Dervish and more geared towards a combat rogue. Is SWS 3/Rogue 17 worth bothering with? I could throw the Swift Ambusher in so I'd get grace and dodge bonus levels (meh). I wanted more Int synergy which is why I was toying with Invisible Blade initially, but I have no idea how combat effective that would turn out. Any other build suggestions?