(Sorry to bother you if this is pie-in-the-sky BS.)
Using Meph's tileset, I adjusted my dfhack init to include:
multilevel 15
multilevel shadowcolor 0 0 0 0.6
multilevel fogcolor 0.1 0.1 0.3
multilevel fogdensity 0.25 0 1
Shadows might be too dark for some and the fog is denser (fogcolor is vanilla) but I can always tell which level is which (I guess not being used to it I was having a hard time on adventure mode) and I also get the full 15 levels.
So thanks to you both (mifki for TWBT and Meph for the integration), I love being able to see lower levels and if I go high enough it's sortof 2.5D Dwarf Fortress. Tried stonesense overlay instead and it isn't super usable and I don't really like how it looks (I keep the visualizer up still on the side, I don't mean to denigrate it).
I've looked through the source code but I'm out of my depth, and I'm curious:
Is it theoretically possible to see levels that are higher than the current one, while allowing clickthrough to the current one of course? (with extreme transparency perhaps). I'm thinking just sortof a suggestion as to what is above the current level. I understand that in some mountain forts that many extra layers would combine to make certain areas unviewable so it'd probably need to be limited to a certain number of layers, but it would be nice to be able to see sortof a full view of what is going on.
I have some examples below. Actually trying to use this might be a pain in the ass, but I think if some translucency could be achieved (better than what I can do overlaying images in GIMP, I was trying to lighten the overlay along with having the opacity lowered but that would mess up the whole picture, and my TWBT shadow settings on the overlays make this a little too dark to work) we might be able to have a sort of 2.5D DF.
Below I've posted the original start I'm using, then overlaid transparent versions of several levels (enough to reach the top of the trees) over the regular view, using 25%, 37.5%, and 50% opacity: