This might be a little too outside the box and is a little more than $40, but I just did the NYC 5-Boro on one of these. The congestion makes it more of a cattle drive with 30,000+ other riders. After 10 hours of pedaling, waiting, pedaling waiting... the trip odometer was over 50 miles (includes getting to and from event). My hands were a little tired, but no saddle issues:
www.harderbikes.com

Pics of its fixed gear cousin:
http://publicbounty.com/