I'm trying to design a disco ball with lettering on it. Is there a clear guide to making one? I found a link on youtube but the writing was far too small.

To my understanding, a disco ball is a polyhedron....ball wih maybe 100 faces, each face is covered with a mirror. So you must be looking for something that's like a disco ball, except not with a mirrored surface. Otherwise, you'll only have backwards text (text in a mirror).

Inkscape does have a wireframe sphere extension, but it's not necessarily like a disco ball. In any case, try Extensions menu > Render > Wireframe Sphere.

I do know of a tutorial that sounds something like what you're looking for: http://screencasters.heathenx.org/episode-088/

You can render 3D polyhedrons with an extension.
Only need to have a 3D model in .obj format.
For example use blender to model an uv sphere -with custom face number- and export it to obj.