What type of finish stain or paint?
When mixing the wood types like birch and poplar, a paint finish would be good and poplar paints very nicely. So, going along that route I'd use poplar for the fronts, it works easily and is available at your souces. To stain those two woods and get an even look will be very difficult because of grain and porosity differences. Just my opinion.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
Last edited by woodnthings; 06-20-2009 at 08:01 AM.