Just as a follow-on to my last post, the preliminary science program for Herschel is here:
http://herschel.esac.esa.int/Key_Programmes.shtml
and the only large mapping project I can see is this one:
https://hi-gal.ifsi-roma.inaf.it/higal/
which basically redoes the Spitzer inner galaxy survey but in more detail and with a larger range of frequencies.
That will be exciting when finished (probably in a couple of years).
I do hope that more large surveys are added. For example, it would be fantastic to have a larger survey of the Cygnus region beyond the more focused one mentioned here:
http://starformation-herschel.iap.fr/hobys/cygnus.jpg
But perhaps that depends on how long the coolant holds out.