There are a number of seminar events spread throught the country similar to what your proposing, such as the SRS and SPLASH events in Minnesota, as well as the Purdue Forums in Indiana.
Most of these events are usually geared towards younger or lower-performing teams, and talks often focus on basic, core concepts about the engineering and non-engineering side of FIRST.
Could you clarify how your event differs from these? It sounds like you're aiming for a similar event with topics at a higher level, like the seminars at the World Championship, but I don't want to assume what your intentions are.
