I've contemplated rebuilding the seats in my B ext cab with all new cushion fabbed in a custom layout. It might be worth a try. Foam isn't too expensive and I've never done it before either, so it might be harder than it seems.
That would be cool. But think about expenses, you could find a junker with some nice seats and swap and do a little fab for cheap or just go with what you feel is right and to your capabilities.