Ray -
Don't know if you have been to Compton, but the American Broadhead Collector's Club (ABCC) had their meeting there this year and voted to have it there in 2010.
We had the entire building filled with mostly broadheads and arrows.
Some of the guys with larger collections only bring a small fraction of their collections because of the very limited space at Compton which I believe is roughly 50' x 65' of display space, or over 3,000 sq feet.
I would guess for bow collectors you would probably need at least 2 or 3 times as much space depending on how many guys came and what they brought.
You would have to establish some specific criteria for the show, such as exactly what could be shown, cost of the tables or space for display, if you wanted to feature one of more of the largest collections of specific bows, etc.
In the past many of us who have shown collections of broadheads, arrows, bows at different functions and have portable displays that can be transported fairly easily.