That's a tough question - steak and white wine are not a very good combination; the heaviness and flavourfullness of a nice rare steak tends to overpower the flavours of the wine. However, it still is possible to manage.
Personally, I'd try to steer them away from Chardonnay, Californian or otherwise, and more towards other grape varieties - Chardonnays can be overly oak-influenced and too supple for steak, better a more firm wine with a good acidic backbone.
My first thoughts would go to either a dry Alsacian Riesling (Riesling is a white grape that is well known for being adaptable to any sort of food) or a white Rhone wine (such as a Chateau-neuf-du-Pape, Hermitage or Condrieu), which are full bodied, firm, and very flavourful. If you wanted to try something different, an Austrian Gruner Veltliner with some age to it, with it's aromas of lentils and spice, should go nicely as well.
If it has to be a California Chardonnay, then my advice would be to go for the boldest one you can afford - Sanford, Grgich Hills, and Landmark Overlook are three California Chardonnays that may suit your needs.
Enjoy!