LÖVE

Could always consider Cg. nVidia's Cg toolkit works for both openGL and DirectX. It's also cross platform (Windows, Linux, Mac).

http://developer.nvidia.com/object/cg_toolkit.html

Performance loss over directly doing shaders in HLSL or GLSL is, with most modern hardware, negligible. Also works on both nVidia and ATI cards.

I really want dynamic lighting implemented now perhaps integrated into box2d?

Pump for some kind of shader support.

My game is going to look awful without it, unless I double the texture resolution. Which brings my game from 170mb(256x256x16) to an unacceptable 600mb(512x512x16). Just for the terrain. My terrain is dynamically generated and not loading from static textures, so I can't simply "unload" them without destroying performance.

I was thinking this the other day, when wanting to get that 2x pixel style. obviously you can do workarounds for something like that, and you could use shaders for so much more, but just putting in my support, at least for reading the colour of a pixel on the screen (so we can do our own shaders at the end of draw that could use points rather than pixels.). that would probably kill performance pretty well though.