hi, thanks for the example file.
I tried many things to get this working.
Blender is not the only program that has trouble with .sgi format.
Inkscape: Won’t open.
IrfanView: Opens but is a poor conversion. 8bit?
Xnview: Opens but cannot save properly. no sgi save?
So I opened your sample .sgi with Gimp.
Then I saved the file with “No Compression”
The nice image then imported/opened in uv/image editor in Blender correctly. (hopefully in 16bit!)
Unfortunately, this means you would need to Batch convert your files first before importing into Blender.
I know a workaround is not what you really need, but often in CG,
workarounds are needed to simply get the job done.
I do hope this helps.
As for adding support for this in Blender, you could still file a bug report, that Blender won’t open your file correctly.
btw, cool reflections in the image. =)
Edit, running the image through Gimp also fixed some of the problems in the other Image Programs.