Cool VL Viewer v1.26.22.38 included this feature (as a Mac user, I got it in Catten's v1.26.22.43 built):
I've been puzzling over why I could no longer see my rigged mesh RP pressure-suit in mouse-look, and solved it last night by checking the "Show the avatar rigged head attachments in mouse-look" box. It appears that leaving that box unchecked causes
all worn rigged mesh attachments, not just head attachments, to be invisible in mouse-look. If that is the intended behaviour, possibly the description text on the checkbox should be updated?