Shader only needs support for point lights, I can do that easily enough.

Interesting approach, however, this would illuminate the whole object if only a small part of it were inside the light's range. I'm looking to have the only the parts of the object that are within the light's range illuminated, hence why I'm trying to implement it as a shader. Doing the calculations for every vertex is what I want.

No, that's only the position of the light, not it's range.