Reference to Thuthu’s suggestion:
I know that luminous plaster does not in fact create any light. So what if you had a slightly different block that DID glow AND if you had a backwall of glow plaster and you place another block on it, it should behave like a block with an embedded light, but with that block’s appearance. In other words, you could make a creation out of any materials you wish, and they wouldn’t need additional lighting if placed on a glow plaster back wall.
Option 2: Rather than placing a block on glowplast back wall. It could instead be designed to work like a trapdoor and the glowplast block would take on the texture of the block next to it, but still give some illumination.
A glowplast block should only illuminate with a soft, subtle glow, but enough to eliminate dark patches in constructions. Maybe by itself it illuminates somewhat less than a torch but with the clear white color of a steel lantern.
Recipe: 1 block of luminous plaster + 1 lantern = 1 glowplast block