I've made a mod witha new mk28 using another 3d body although the look in the torpedo loadout is still the same :
here when fired from bow:

and a mark 31..
you'll notice on the torpedo loadout screen that there are also the mk31 and mk35, but when in game they are seemingly replaced by mk28s. have to work that one out, but the wip mod is available for download as of now at :
http://hosted.filefront.com/keltos01/
enjoy !
Keltos01