Hey,

Thanks Ryan for your answer. But I'm totally agree with you Abilnet. Multilingual features is nowadays a real necessary for many websites.
To make it possible with Ubercart, I think that the solution may be to change the way Ubercart handle the catalog vocabulary. But the problem is that we can select only one Catalog vocabulary in the store Administration...
I'm still working on it. But some feedbacks from people that had success (or not) on making multilingual Ubercart website would be nice =). I'll let you know if I find something.

my 2cents from Rainy France