Projector-type 3D scanning seems very functional, but I would expect it to lose accuracy as the object size decreases. So for scanning small objects (such as Lego), Lego genius Philippe Hurbain has come up with a scanner made of lego.
Philippe’s instructions also includes (under “3D reconstruction”) a technique for creating a “complete” 3D model out of several combined scans, using open source 3D software MeshLab.
More information (and via) Dansdata
Lisa Parra and Sophie Barrett-Kahn were using legos for their 3D scans, but to control lasers and using DAVID instead.
Projector-based/structured light scanning still works on small objects (actually, even better since there's a potential for more light and therefore less noise on the image sensor).
Where this will work that neither lasers or structured light will is on non-diffuse surfaces. Highly reflective/mirrored surfaces and glass surfaces can not be scanned effectively by structured light/lasers, but this would work great!