Reproduced with r12954 on OS X 10.7.5: the template dialog displays the fallback image 'Linked image not found', instead of a picture showing the page size frame.
Note that even r12953 doesn't render a preview of the actual SVG template (e.g. with predefined visible objects):
** (inkscape-12953:30809): WARNING **: Including svg images tags is not yet supported.
but at least it shows a preview of the page frame proportions.
Reproduced with r12954 on OS X 10.7.5: the template dialog displays the fallback image 'Linked image not found', instead of a picture showing the page size frame.
Note that even r12953 doesn't render a preview of the actual SVG template (e.g. with predefined visible objects): 12953:30809) : WARNING **: Including svg images tags is not yet supported.
** (inkscape-
but at least it shows a preview of the page frame proportions.