The definitive conference for 3D printing seems to be Euromold, a large manufacturing conference held in Frankfurt, Germany each November. It's called the "World Fair for Moldmaking and Tooling, Design and Application Development". Yes, it's the big one.
Euromold has existed for years providing information on manufacturing, but within the over 1000 exhibitors are found many 3D printing companies. In recent years the amount of 3D printing exhibits has dramatically increased due to the explosion of interest in the technology and now Euromold is the place where many major 3D printing announcements take place.
At this writing there are 18 3D printing and 29 3D scanning vendors listed, including both large and small players. Software providers will also be present.
A word of caution, however: Euromold's web site is quite confusing and often it's difficult to find desired information.
If you can, please make the trip to Frankfurt for this huge conference. We'll be there.