Carrying on where I left off, R2-D2 now has sections cut out and rebuilt to house lighting at the front...
...and at the rear.
Speaking of the rear of the unit, I created all of the panels around the back. Some of the lower sections were straight copies from the front, just rotated into place.
Finally, I exported as an OBJ, imported it into Keyshot, threw some materials on top and rendered the following picture. Click for full size.
There's not much left to model before I start UVing and texturing.