Hi Vic. I've looked at the PassPort Sling. and I don't think it would take two bodies, with lenses. The padded section is really meant for one camera + lens, and one lens, in a padded compartment fold down. I've extended the padding along inside the sharp end, so I can get 4 small lenses, or three if I take the 135m and a zoom. Also, all my lenses are in neoprene pouches. These offer a bit of protection, but are maddening, because you can't tell what lens is in which pouch. I thought of labelling them, but that would mean carrying an extra pouch, and remembering to put them back right.
However, you may have noticed the expansion zip on one end of the bag. With this unzipped, you could fit another padded module in easily. There are loads of those in different sizes on Ebay. The bag as it stands, without the expansion zip undone.
I was thinking about getting a larger one myself :-)