Probably would be a bit of a trick, but using multislider is great and it would be even better to see exactly how many "bricks" / units are highlighted in each slider. Obviously just for ints and would be most useful at low numbers.
For what I'm doing now I'm supplementing the multislider with a jit.cellblock to accomplish this grid-view, and while the cellblock looks better and has more options for colors etc., it's substantially more work to deal with because of the row / column thing, as well as not easily being able to "paint" like the multislider, or save in a preset.
An option to turn on and off a grid for the sliders (and a grid color choice) would be cool. It would only be horizontal probably, since one can already change the slider spacing and that would be messy (I imagine) to follow with the grid overlay.
Perhaps there could also be a mode where the slider outputs (slider, value) out the right outlet without having to send a fetch $1 command. This is like cellblock's left outlet. Seems like it could be done as the slider tracks all your clicks and drags anyway.