Not sure if this was already suggested, I did my best searching.
I was trying to light my underground base just now and let me tell ya, I was having a heck of a time dealing with the few options we have. Torches, Lightstones and Luminators which aren't quite feasible yet. I hate looking at sooty torches, and I dispise the stock look of lightstones. Even with texture mods they don't quite fit in. I tinkered with the idea of setting them back begind glass to minimize their appearance, but it's only a half-solution that doesn't look the best. So I said to myself "Myself, there needs to be a better way to do this!" And then it hit me.
tldr;
THE IDEA:
A white block that looks somewhat like a luminator (but is a full cube, like hardened CF) that doesn't block out light. In fact, it glows at the same intensity as the light currently occupying that square. Put a lightstone behind it in a wall, and it'll look like a nice light! Heck, add the Painting functionality and color your 'light'. A more advanced idea would be to actually color the light that passes through, changing the color of the light itself if that's possible. (making my purple and pink love-nest possible!)
Of course it could be more complicated too. Like if you set another fiberoptic block next to it, it'll glow at the same intensity as the first. Use them to create neon signs! They wouldn't actually radiate light, but simply glow as bright as the brightest one in the length. Or maybe they could? Give them a maximum length to prevent abuse. Heck, how about linking them with the Luminator project to create.... FLORESCENT LIGHTS! 
There are so many ways it could work. In any case, that's the idea. How do yall like it?
I should have linked the test rave! I'm sorry! 