Since getting steel wheels (without wheel covers) and winter tires installed, the rusted "hub" (a three inch in diameter circle at the center of the wheel) is now exposed. Initally, I was going to get Civic DX wheel covers in order to cover up the rust. However, I noticed an old Accord the other day, with winter tires, that had a little cap covering up the three inch in diameter-or-so area. Does anyone know if there are similar caps available that are compatible with the 2006 HCH? Thanks.

Try going down to your local Home Depot electrical department and look for the circuit breaker box hole plugs. They come in various sizes, and you should be able to find one that will fit on the rim to cover the center hole.