The shorts made by Ground Effect in New Zealand don't have elastic leg bands.
http://www.groundeffect.co.nz/index.htm
I have both the Jitterbugs and the Mojos. They're well made and reasonably priced - the Jitterbugs are under $60 US. The lycra they use is very soft & stretchy. The shipping charge from NZ is remarkably reasonable as well.
A few of us here have been singing the praises of Ground Effect, do a search and you shall see. 
Just bear in mind that they run a little on the large side - if you're in-between two sizes, you might consider ordering the smaller size.
2009 Lynskey R230 Houseblend - Brooks Team Pro
2007 Rivendell Bleriot - Rivet Pearl