I would agree with some of the others and say you'd probably do better on ebay than on DP.
with that said, you would have to have a pretty thorough lens with lots of good quality content, PR, Backlinks etc. If you are already going to spend that much time, I would much rather buy a good niche-related domain name, use a simple template, and add the content to my own site. Get some good backlinks, start getting traffic, monetize with Adsense/ad network of your choice, and flip the website instead.
While Squidoo has good PR/Alexa ranking, this is looking to me a lot like when people were trying to flip blogger blogs. Just like Blogger, Squidoo is a free site, so if someone wants to get a good lens, they can just make it. Somy question is why would someone want to buy it?
Now there are going to be the lazy few who don't want to do the work...
I just am not sure it's a very good business model unless there is a huge demand for pre-made lenses...flipping websites just seems more profitable to me, but what the hell do i know right?
That's just my 2 cents...
On that note, has anyone had success selling a Squidoo lens?