These sites may give you some ideas to get started:
http://store.velo-orange.com/index.p...ts/cranks.html they have a 48 X 34 double on sale
http://www.rivbike.com/Cranks-Chainrings-s/41.htm even lower at 40 X 32 and 40 X 26
Here's a gearing calculator which allows you to graphically compare two drivetrain choices:
http://www.kstoerz.com/gearcalc/compare/