Hi all, I'm looking for software that allows me to draw and use layers in pretty much the same way I would in GIMP or Photoshop, only projected onto a globe. I've tried 'painting' in Fractal Terrains but find this tiresome. It's slow, unpredictable (ok, not per se, but since its main use is for generating terrain by fractals it really doesn't facilitate freeform drawing, you know what I mean). The thing I like about FT is that it features some classical map projections which indeed would be very useful when it comes to exporting a finished map. I'm really not after the detailed topographic rendering at this point, because I know that FT doesn't handle it the way I'd like it to, and I've gathered that there aren't really any other programs doing this in a realistic way (what with plate tectonics and all) so atm I'm going to try to model it all by head.

Basically I want to see a globe projected in whatever way I prefer (just as in FT) that I easily can move around and add layers to (prevailing winds et al. - all by own design, so nothing fancy is needed here). Of course, this is possible if I do some work in GIMP, then FT, then GIMP, then FT, then GIMP and so forth ad nauseam, haha. This jumping back and forth is what I seek to avoid.
I have some slight experience with 3D-modelling software of the advanced sort but I really want a program where adding layers isn't a hassle. Do you guys have any suggestions?
Thanks in advance.