I want to try a campaign where, while NPCs and monsters use the standard stuff, almost everything the PCs have is customized by them.
The PCs won't choose a class. Instead, they'll buy abilities with class points. I want to give them enough points to edge over NPCs slightly.
Most of their gear will be custom built by them (piecemeal armor, custom weapons, and custom vehicles).
Their magic will use FFd20's MP system blended with Words of Power rules.
Any suggestions?
A different system like Scion or a White Wolf game may be a little better for the concept, since they use the ability buying system you're describing. It's easier to alter the setting in a different system than convert the whole system for an idea.
That said, I would avoid doing such a thing with Pathfinder. It's very class and level oriented. Between vatiant multiclassing, gestalt, frontloaded classes, and feats, there's enough diversity to the base skeleton of a character to do pretty much everything.
Pathfinder is not a good system for this. A better solution would be to use another system Hero System is exactly what you are looking for. Everything is built using a point system. Even the equipment is built using the same rules. The only difference is in a heroic level campaign equipment is not purchased with points. It is either found as treasure, or purchased with cash.
I don't know if I entirely agree with the others... It's possible to do this well, and even has me writing down ideas to do something similar...
The only real problem is to make sure that a full BAB is so costly that you can't purchase even mildly low magic (the only way to afford magic being to not get it until much later in the game). The main things players will do is try to get a full bab -with- a great potential side-power.
Similarly with a full magic tree... shouldn't be possible to afford even a middle bab if you have a full magic tree... Other than that, I like the idea of being able to mixup your own abilities... it's not really different than just allowing them to homebrew their own archetypes from scratch (which I almost always end up doing with my players).
That being said... even though I like the idea... I do think it's far smarter and balancing to just write up archetypes that match what they visualize. I tested this out with a friend, and basically he started with trying to build a natural-attack character who could start with a full bab with multiple natural attacks, and a pounce ability. Expect that sort of mentality... :)
What this really entails is writing a different game system. While it is possible to do this, what you end up with after you are done is no longer Pathfinder. It would probably be easier to start completely from scratch instead of altering a game system that was not designed for it.
If not actually using the system itself, I would recommend looking for ideas by reading over Mutants and Masterminds (SRD is here) which is a d20 based point buy system. It's used for superhero games but it can emulate any system, really, and you can see how to build up point-based abilities. Furthermore, it's about a billion times easier to grasp and build characters with than the HERO system with still 98% of its flexibility.
You could also look at M&M's cousin True20 which is not point-based, but is an adventure system boiled down to I think(?) (been a long time since I looked at it) three modular base classes (basically warrior, skillmonkey, caster) that can choose a variety of abilities to customize their focus--and then Pathfinderize that or take some of its ideas into Pathfinder (i.e., don't completely eliminate classes, but build a basic "chassis" classes your PCs can then uber-customize with buyable abilities or archetype packages).
I was organizing my PDFs and I found Eclipse: the Codex Persona among them. It looks like another Character Point system. Anybody have experience using it?
It's been tried. Many, many times. It's generally easier to play a game designed with that sort of thing in mind than it is to attempt to shoehorn such a change into Pathfinder and then attempt to fix all of the now-broken parts of the system that depended on the class paradigm. But go ahead and try it out! Alternately, discuss with each player what sort of character they want, pick a reasonably close base class, and design a custom archetype for it that makes sense, with the understanding that the archetype may need to be revised as the character levels up and the player wants to go a different direction.
I don't know if I entirely agree with the others... It's possible to do this well, and even has me writing down ideas to do something similar...
The only real problem is to make sure that a full BAB is so costly that you can't purchase even mildly low magic (the only way to afford magic being to not get it until much later in the game). The main things players will do is try to get a full bab -with- a great potential side-power.
This is already possible with existing options--you don't even have to leave the core rulebook, though it certainly helps--but I agree that one shouldn't make it too easy.
The old 3.5 book Unearthed Arcana had an option for building characters using three "generic classes. You would start as either an Expert, Spellcaster or Warrior as the main chasis. Class features such as Evasion or Smite Evil were turned into feats with various prerequisites. I suggest looking into this as a basis for what you're trying to build.
http://dndsrd.net/unearthedNewClasses.html