If you don't mind the extra work, you can remove the doors from their hinges (probably only one pin per hinge) and sand them thoroughly. If you sand them, you'll need to get off all the old finish, else they come out looking spotty.
Once they're sanded then simply pick out the lighter polyurethane finish you think you'd like. You could test it's color on one corner, though you'd have to re-sand that area once you decide.
We've finished some similar doors here in the U.S. and I finished them in a "washed oak stain"... but you could pick out anything that catches your fancy. Stay with polyurethane for cleanability and gloss. You could then change out the hardware, including hinges readily, going with a contrasting color such as oil rubbed bronze(seen here:
http://www.edirecthardware.com/articles/oil-ru bbed-bronze-cabinet-hardware.html ) that's so popular over here right now.
None of this would be terribly expensive... just labor intensive... Best of luck!