Yeah it's a colossal amount of data that needs to be processed to get the end result, I mean the complete animation of one sprite is made up of 6 files at least.
I actually had the NANR bank types in my implementation (excluding knowing what the extra data did), however I must have thought it was wrong and removed it. Silly me :p
At the moment I've been trying to figure out the cell gap problem, and my current assumption is that if the vflag == 3 an offset is added based on the x & y coordinates, much like how with the Digimon World sprites (which I think are vflag == 2) add/subtract 256 if the x coordinate is <=-64 or >=64. I can get sprites to display within about an 80% accuracy but I'm doing it the long way so it's sort of trial and error atm. The key thing that helps support my assumption is that when you load up everything up to the NMCR file, the body parts line up better with the feet generally just above to horizontal center point (red line in my gui).
I'll add support for any formats with a clear indication of what they do (ie structured header, documented, etc), but my priority is getting the more generic ones supported first, specifically right now I want to have all the Nitro and Nitro3D formats supported. At the moment, it can open NCLR (as well as the other stated palettes), NCGR, NCER, NANR, NSCR, NMCR and NMAR with varying levels of functionality, with the most supported being the first 5. As far as my current milestones go, I've only got to add support for NARCs and probably DS Roms, plus finish up the drag and drop ui, before I'm going to be happy releasing a build so people can start testing it :p Though as I've said I've kind of sidetracked at the moment trying to fix errors in the NCER and NANR, depending on how they go I'll get stuck into the rest later.
Not having much luck with the cell gap bug. There is almost always two conflicting cells that if you fix one, it breaks the other, so perhaps there could be another variable involved, such as the u16 value in the bank header? The issue though with that is that other NCERs have values stored here also.