Thanks also go to Adam for pointing out RM’s Test Authoring System which claims to be fully compliant with IMS QTI 2.1, making it one of the earliest commercial products to implement the revised specification.  I couldn’t find a demo to try out, but it is good to see the specification finally being implemented in this type of system and market sector.  Also on the website are also a couple of research reports on the impact of ICT in the classroom which are well worth reading.