It would be nice to get some confirmation either way on the logo, idents and graphics.
My take on it is - the logo will not change - The music and idents will - The general layout of SSN if it goes 16:9 will resemble At The Races (which is basically 16:9 version of the SSN on-screen look)...
I could be completely wrong but I would have thought even when SSN goes HD next year that the regular SD channel would remain 4:3,as presumably the benefit to premium subscribers of the HD version would be the extra info on screen in addition to the better picture quality,obviously.