Is Rottela T 5W40 still availible? Today a checked the ussual places for it, Wal-Mart, K-Mart, Auto Zone, and Advance Auto and found nothing. Everyone seemed to have the 15W40 but none of the 5W40 that my bikes like.
All the major auto parts store chains in So. Cal. tend to carry 15w-40 diesel oils, and only that weight, so you're in good company. You might try a NAPA or other auto parts store which also carries some amount of heavy (big rig) truck parts. They often have a wider selection of diesel lubes.
I haven't tried it on Rotella 5W40, but typically if any Wal-Mart carries an item, the other ones can order it. So, you might consider that option. When the Rotella 5W40 is avalible for ~$12/ gallon, even if/when Delvac 1 is readily avalible, it is still a pretty good deal.