If it was not already mentioned, there was a Belgian company that made very nice oval chainrings in the 30s-40s, called Thetic (for Theta, the Greek letter it resembles). I have picked one up which will go on one of my recent acquisitions. I see them on ebay from time to time. And I just got a new book called The Noblest Invention, published by Rodale which is a collection of articles and photos that is a history of the bicycle, that shows a Humber from the late 19th century with a decidedly oval chainring. Page 154. Book available from Amazon.com by the way.
In defense of Shimano's Biopace, I've always felt it got a bad rap. Shimano spent a great deal of time and money developing the design from computer models and studying cyclists and their efficiency. The Biopace is the result. The idea of it is that you speed up your spin on the most efficient part of the stroke, the downstroke, and slow it down in the dead spots. That may seem counterintuitive to some, but the net effect is, you are slowing down your spin overall, which is more aerobically efficient, without endangering your knees by pushing too hard through the power cycle. Not that I use them on a regular basis, but I have racing biopace on my Davidson Impulse #1, built in 1985 (sorry if it is later than on-topic, but someone else brought up the subject) I used them for a few years on that bike and thought they aided my out of the saddle climbing, because I don't like to spin while out of the saddle, but this gave me more juice in the downstroke while spinning at a lower cadence. The racing biopace were less out-of-round than the mountain biopace and were only made in 42-52 sizes.
And in regard to triplizers, at the risk of getting called for offering something more than once to the list, I have a professionally machined jig to drill Campy arms to add any 74 bcd chainring. I offer this service to my customers for $30 plus the bolts and ring. I have a lifetime supply of Ofmega bolts to go with for $20/set. I think this is much nicer than a triplizer. Many chainrings will fit but the nicest are from TA which cost about $30. I've been doing these for 15 years or so and no bad experiences yet.
Bob Freeman Temps are coming up but the ice and snow is hanging in there in North Bend WA