The iPad and Penultimate worked well for these rough concepts. I was able to get several ideas down quickly and email them directly to David from the iPad for review.
Inking and Production
With the concept and general direction set, I brought out my large Moleskine sketchbook, penciled in the rough imagery and began inking the pipeline, landscape, space ships and several bits of hand-drawn typography.
Here you can see the pages where I inked the illustration. Note how pieces are spread out on the page and not in any specific order — that's because I scan the pieces and assemble them in Photoshop. This approach provides control and lets me make changes quickly.
Once the pieces were scanned and assembled, the final slide looked like this:
I was very happy with the end result. Having just finished watching Mad Men Season 4 last week, I was definitely channeling 1965 into the final illustration.
David was very pleased with the results as well:
UPDATE - David mentioned this article on the 37signals blog, Signal vs. Noise.