Hey Lostboy, seems we have a bit in common, I'm also from a motocross background and have recently fallen in love with the classics (after cutting my teeth on two brit builds - '69 Bonneville bobber and '58 Triton), being a Honda fan the next step was always going to be CB.
I bought a CB550 and loved the style of cognito moto's bikes, he runs gsxr forks and motard 17" wheels. This may cause hassles for competition, but here in South Africa we have more of a parade race, with some racing in amongst the guys, but nothing too serious, so I'm hoping the wheels etc wont be an issue. I'm basing my CB550 on the CR750 loosely. I just want something fun, with modern parts where performance counts.
Kevin Bidgood has done a whack of mods to the engine, but not sure yet what sort of HP we'll see. here are a few pics.