alex,
The reason IB doesn't offer the ND contract is because it is open outcry. Keep in mind if you are thinking about trading small sizes (1 & 2 lots) I believe you will have a difficult time getting a decent and fast fill in the pits. At least this is the experience I've found in the S&P pits where executing a 10 lot is much easier than a 1 lot. Thus your success in trading the NQ's may not translate well in open outcry.