It appears that PROC EXPORT still uses the SAS v7 (then current) max label text length. Oddly, the LABEL option was just added with SAS v9.2, I believe.
You may also notice in the SAS DOC for EXPORT that any SAS variable that is longer than 32 characters is also truncated (without the LABEL parameter of course). Likely doesn't sound like it will be considered a DEFECT, given this condition.
Regardless, it's important to contact SAS support to give them the feedback on these types of limitations rather than presuming they already know.
Scott Barry
SBBWorks, Inc.