The major news is that, after some discussions on the appropriate name for the group ISTI does, indeed, have a new group ... the Parallel Observations Science Team (or POST) led by Victor Venema and Renate Auchmann.
You may recall a number of posts on this subject over at Victor's place. We shall work with colleagues to help further this effort. By being part of the formal ISTI family we will ensure that benefits regarding data holdings, benchmarking, and lessons learnt from this effort are more broadly shared. We always look for win-wins!
We are still looking at populating the parallel measurements database so if you know of any coincident measurements using distinct techniques or looking at spatial variability at the local scale (or both) then please do get in contact. Victor and Renate are also still populating this group (terms of reference here) so if parallel measurements are of interest and you feel you could contribute drop them a line.
More details on this effort can be found at http://www.surfacetemperatures.org/databank/parallel_measurements