Kogs,
That 11.4 is just my best time in a match sprint. I'd need to do better than that in a flying time.
Good luck with your frame. There's an opportunity for a real track frame, what with all the road fixie designs out there today. I don't think you need to plan optional trail designs -- just pick one since new riders won't know what to pick anyway, and the rest of the bike (and rider weight distribution, position, and maneuvering style) will affect steering needs anyway. Target a fairly short (but not radically short) trail such as you've described above and you'll have a fair bike for most tracks. A 6 cm bottom bracket drop will be sufficient for most US tracks and will help moderate any handling issues (a typical keirin frame still runs about 5.5 cm drop, and I've seen small-sized high-end carbon frames running at 5 cm).