I guess our major concern is really scaling of the images when you increase or reduce the resolution size. For the most part, that is.
Unless you generate the graphics on the fly, you're not going to be able to scale them infinitely. What Xanather mentioned is the standard way of achieving scalability for rasterized rectangles. Other than that, I would render to an OpenGL surface or image file using Cairo (or similar):
So why would you want to mix vector-graphics rendering, provided by cairo, with OpenGL in the first place?...
- Create pristine texture-maps, which are resolution-independent and combine those with your custom mip-mapping.
- Have animated vector-graphics as head-up-displays or overlays in your OpenGL-program.