Mark,
Yes, I did multiple rides at each distance. For you, and anyone else interested, I have scanned my complete 1983 report, and you can download it from http://www.rrtc.net/baumel_short_cal_1983.pdf (this is 12 pages long, and the PDF file is 1.1 MB). My experimental protocol is described on page 2; my raw data displayed on page 3, and a summary of the data (including the numbers plotted) appears on page 4.
In addition to performing this 1983 experiment, I was one of the participants in Pete's 1985 experiment, and in that case, I estimated my "wobble distance" as only around 3 cm, or about half what I'd estimated from my 1983 experiment. Some of this may be random, but some may be explainable by the different experimental protocols. In my 1983 experiment, every ride on a short course was treated as totally independent (every time I stopped the bike, I wrote down counter readings and then spun the wheel to reset the counter to a round number before restarting). In Pete's 1985 experiment, the stops were much briefer: No data was recorded at any of the intermediate points (and there was definitely no resetting of the counter); we just restarted immediately after stopping. It's possible that in this situation, cyclists don't wobble as much when restarting.
It's also interesting that some cyclists (including you, Mark) appear to exhibit a negative wobble effect (smaller constant with decreasing cal course length). How can this be explained? I had assumed that the dominant effect would be wobbling when starting and/or stopping. But perhaps some cyclists proceed for a significant distance when starting and stopping without their full weight over the bike, and maybe in some cases, this dominates the wobble effect. Moving the bike without your full weight over it results in a larger effective wheel circumference; thus, fewer counts.