Any Flash that will TTL with Canon & Panasonic?

[jetabout]

Hi everyone,
I have a Panasonic GF1 and a Canon G11. Is there a flash that will work on both ? The flash should be able to TTL (not manual) and preferably able to do 2nd curtain syn.

Olympus flash will work on Panasonic as well. So if it works on Olympus and Canon, that will be something I like to look at as well.

Thanks for the help in advance.