Preliminary "Ribbon&qu...

About efficient drawing with a continuous construct: this can be achieved using a OpenGL indexed vertex array, of type GL_TRIANGLE_STRIP, First construct an array of vertices where each vertex appears once and only once (so, for each of the small cylinders you currently draw, take only the "bottom" vertices, while the "top" vertices will be replaced by the next cylinder's "bottom" vertices). Then construct the separate index array. It's an array of ints telling OpenGL in which order to use the vertices from the vertex array to draw the GL_TRIANGLE_STRIP. The trick here, allowing you to easily join a cylinder slice to the next one, is that it is perfectly allowed to draw flat triangles. This is actually a very standard practice. So you can e.g. repeat a vertex twice, or do a A-B-A sequence, leading to a flat triangle in the strip, which won't be drawn at all, but will allow you to easily assemble together the slices into a big GL_TRIANGLE_STRIP.

Oh I just had another idea: why not take the orthogonal point of view: instead of slicing the tube into small cylinders, you could slice it in the orthogonal way, in long "shoe laces". The advantages are that:
1) building the shoe laces GL_TRIANGLE_STRIP is much easier and doesn't require you to add flat triangles
2) the number of required shoe laces is independant of the length/complexity of the ribbon, it only depends on the required visual quality, and probably doesn't exceed 15 or 20.

The disadvantage is that your vertices are no longer sorted by locality, which may harm performance depending on the OpenGL implementation.