I really like this style.
I plan to do it.
But I need to find a way to test it quickly everytime, is it a old fashion way to test 32bpp sprites without newgrf ?
using .tar maybe ?
The whole theme can be done quickly if i manage to get easy preview of my work everytime
It's indeed a nice idea.
There's only the grf way. It's fast as well.
Compiling a simple grf which only replaces ground sprites is not difficult and has really simple code. Look at zbase (for how to use 32bpp) and ogfx-landscape (for how to make a simple newgrf for landscape replacement).