We do a predraft event every year. I'm pretty sure its the biggest and maybe oldest "independent" predraft. Usually about 40 players, most recommended to us by MLB scouting departments. We do it at our home field in Cedar Rapids, Iowa. Typically well over 100 scouts attend. In some years there will be several scouting directors, even some GMs and other front office people.
We do ours in May, about three weeks before the draft. Its a one day event.
The type of players who have attended in the past that ended up being high draft picks or became Major Leaguers include...
Ryan Sweeney (IA)
Brian McCann (GA)
Carl Crawford (TX)
Jeff Clement (IA)
Thomas Diamond (LA)
Jonathan Arencibia (FL)
Tyler Clippard (FL)
Jason Berken (WI)
Lance Broadway (TX)
Trevor Crowe (OR)
Bobby Livingston (TX)
Brad Nelson (IA)
Joe Bisenius (IA)
Wade Townsend (TX)
Joel Hanrahan (IA)
Jason Jaramillo (WI)
Wes Obermueller (IA)
Brad Furnish (TX)
Trevor Reckling (NJ)
There's actually too many to mention them all.
At this event, they do the workout and we play one very long game. Everything is geared to the scouting departments. Lots of talent. Its kind of fun!