Another vote for a paint tool, again. A tool that will allow us to paint any block wall, or plank and beam to any color using a color picker (hexadecimal selector). Perhaps we would first have to have a "null" texture (represented by plain gray, maybe) then apply "paint color" over that.
So we'd select that null texture block, or color ID for a beam or plank, build our wall or whatever. Then select the Paint tool, and in that GUI we'd select a custom color from a hexadecimal tool (many simple ones on the web). Or failing that, typing in a hex number. We'd then point our Paint tool at the null colored wall and click to apply color. We might repaint, too, if we want to change the color.
I'd also wish for paint to be applied only to the side we touch, but that may be impossible. Even so I'd welcome all-over painting!
Alternatively, selecting a Null colored block or element in the crafting bench or inventory and having a way to color it there with a custom color, would work just as well. OR, doing in the console by perhaps typing:
item woodbeam qty. ID# (color as a hex code)
Extrapolating from that, maybe you could also have some sort of command center where you could input all the properties, item type, material or custom color ID, size dimensions and orientation X Y Z, AND then save that custom object to reuse.
I'm dreaming, so I might as well dream big.