What advice are you looking for specifically? What gear you want to take, what feats you should be examining?
Advance path?
We don't know anything about your Custom Archetype so not really able to help a lot.
When you say "swashbuckling Bard" I think of a rapier wielding fighter that uses a lot of acrobatics/tumbling says "engarde" a lot.
In general this type of build focuses on dexterity and the big crit modifiers. You are going to want to run into a battle stab some guy in the face and roll away. The big problem in my opinion is that depending on the books you have access to this build can be very light on damage and will be feat heavy. The spells the bard has access to might help, as will the 25% chance of a crit but overall your damage out put will be quite low.
That said I still want to play my version of "The Dread Pirate Roberts", because let's face it saying "I know something you don't know", right before you puncture a lung is very cool."
What are the issues you perceive in the Arcane Duelist archetype that prevent it from being what you're after, as it is now?
"The spell ones" -- you mean, the fighter-only feats that allow you to disrupt spellcasting? If you don't like any of the bonus feats, the Arcane Armour, or the Bonded Weapon, what is it that you do like about the Arcane Duelist?
Are the Dervish Dancer or the ArchAeologist, archetypes found in Ultimate Combat, closer to what you're interested in at all?
My Arcane Duelist basically is the swashbuckler of the party, and she's pretty kickass at it so far. Combat casting is free at level two with it. Perhaps your DM would be willing to give you weapon specialization for it instead? The later fighter only feats are all about your sauve swashbuckler giving enemy casters a very bad day.
I dont know about you but it seems pretty Swashbuckling to me to be so incredibly awesome that just by standing near a caster it makes it hard for them to get spells off.
But perhaps one of the other archetypes would be closer to your goal?