Hi, Darkblade, I second Chris about stretched sprue. In 1/72, it can make very convincing ribs and stringers. If you're very serious about a 1/72 biplane, you can use stretched sprue for the rigging, too.
Regarding the instrument panel, it depends on how visible it would be. In an open cockpit, of course, it's probably going to be very visible. I've taken to using thin styrene stock and punching holes in it, then adding another piece as a backing. I paint the whole thing black (well, Tamiya's NATO Black, which is really more of a dark charcoal gray), and put a drop of Future (any clear gloss varnish will do) for the instrument faces. I have a pair of Italian WWII fighters in 1/72, as a matter of fact, on which I'm going to use that technique. One is a Reggiane Re 2001, which has a closed cockpit, but the other is a Fiat G50, which is open, so I need to add something. There are very good instrument decals, too, by the way, but for my purposes, that's a little too much. Mine are a pair of quick, anti-AMS builds, so I don't want to go too nuts.
Hope that helps!