Looking for a script that will generate a grid of empty artboards at a specified size and padding.

Dilliams suggestion is not dumb at all. I'd call it a common non-scriptactional way that works pretty fluently.

One may simplify it a bit by drawing a large rectangle, use the Object menu > Path > Split Into Grid route to create the grid of rectangles, convert them to artboards, set the artboard sizes to whatever is required in one shot by activating the Artboard tool and finally rearrange the artboards with the corresponding command.

here's another (most definitely inferior) way to create artboards in a grid with padding. 

draw a rectangle at the desired artboard size and position. draw a spacer block starting at the right edge of the first rectangle, and having a width of whatever you want the padding to be. shift + option + click and drag the first rectangle to the right until its left edge aligns with the right edge of the spacer block you drew. then use cmd/ctrl + d to repeat the transformation (and since you copied while transforming, the copy is duplicated as well). repeat cmd/ctrl + d until you have a rectangle for each column you want. then draw a spacer block below any of the rectangles you just created whose height is equal to your desired vertical padding. select all the rectangles (minus the spacer blocks) and shift + option + click and drag them down until the tops align with the bottom of the spacer.. repeat transformation until you have the correct number of rows. delete the spacer blocks. select all. Object menu > Artboards > Convert To Artboards.

This is a really dumb way to do it. please.. nobody do this.

but it is indeed one way to do it.