Added link to FDO ticket.
In my testing, it looks as if the MrSID is being parsed properly by the GDAL provider (CPL_DEBUG shows it reading the various levels), but I end up with a white image on my screen.
Using the current version of OpenEV distributed with FWTools, I can see the image just fine.
My understanding is that this image is in CANST-NB83-CSRS which I believe is the same as:
http://spatialreference.org/ref/epsg/2953/ogcwkt/
I tried setting appropriate map extents and referencing the image from the map (to see if it was not showing just because of the extents) but was not successful with this.