Lise - the Terry Zero X is supposed to be good for tri's. Here's the blurb from the terry site:

"Terry's lightest weight women's saddle provides a flared rear platform ideal for increased leverage on climbs and in big ring power sprints. Slightly wider rear than the Damselfly, with a larger cutaway that extends further forward. A flat overall platform and slightly wider nose increase the forward riding surface while in an aero position on the bike, making this a good choice for racing, triathlons and time trials. Vanox rails are as light as titanium and stronger so they're less prone to failure when used on a variety of seatposts. Textured leather surface with matte disks wears beautifully over time and keeps excess movement to a minimum."

I have this saddle and love it! MP suggested it - she has one (Terry Zero). It has very little/no padding, but gives good support and doesn't squish the girly bits. I haven't done a tri YET, but I'm hoping it will work! No problems in the drops anyway. And - TE sells it with a 90 Day return policy