In reply to Gordonbp:
What you need is a pair of these:
http://www.jakesbikes.co.uk/content/778.php#.V3pw09j2Yhc but fitted upside down
I've got some on my Airnimal, which was supplied with a straight bar. Turning them over gives them a very slight drop and orients the bar so that they are slightly thumbs up, in a very natural position. I have some ergo-ish rubber handgrips on them too. Good for 30 miles a day commuting. I had to cut an inch off each end to get the right length.
Jakes don't do mail order though. Decathlon sell something similar.