Definitely not unreasonable - I have supported UK-based companies who use SAS and they typically display/print only date and sometimes the time-portion but as separate columns, rather than combined.
Of course your other choice is to concatenate the two components at display time, creating a character-type variable in the desired format.
Concerning your site's SAS shared foundation - I take that to mean a SAS enterprise environment master CATALOG OBJECT library,where you store various site-unique SAS-related items, such as FORMATs (either display or look-up), possibly INFORMATs, ODS templates, and other tables. Suggest you set this up centrally and provide either a user-invoked macro to concatenate your local OBJECT using a LIBNAME . Look at using the GETOPTION function to retrieve the current FMTSEARCH and conditionally replace it, if necessary.
Scott Barry
SBBWorks, Inc.