After much searching it looks like this is the ideal camera for an aspiring film maker, so I'm looking at getting one used but I'm a bit confused on the models.

I understand the 100 vs 100a thing, but what's the 100AP? Or any other variances out there?

There are no other variants, only the original DVX100 or the updated DVX100A.

Any other notation you'll see is a regional marking system, so DVX100AP is Pacific, meaning for countries that border the Pacific ocean (Japan, USA, Canada, etc...) it's the NTSC model. The DVX100AE is the PAL european model. The DVX102 is the Chinese PAL model -- no new features, just a different identifying model number to track where the cameras are going.

Thankyou! That cleared up some confusion.