I make buttons all the time and it isn't that time-consuming for me.
Well....that's super.
The time here comes from loading the mod and screen printing the LH to PSP. Then I clip and re-size, and use a bracket overlay. I save that file, open it in DXTBmp and apply an alpha channel bracket and save as a DDS. Then I have to copy that file to two sources and ensure that the XML pathing is correct.
That's for LHs. For new buildings and units, I do the same thing but first I have to find art I can use for the button. I like to find applicable images for each different UU and UB, and when you're adding dozens of each, it can take a while.