I know what you're talking about. Unfortunately, I'm not aware of any apps that will help. You might be able to find older versions of PSE, I may even have some disks, I think I started with 9 and I think it had the white background...
Of course, Adobe (and probably most other image editing makers) claim the black background helps cut down on the distractions adjacent colors might cause while editing what's on screen. PSE did decide to offer a lighter, neutral grey app background, but it's also used in Lightroom. "Adobe" (Apple?) always knows what's best for us, you know...
As for 'non-destructive' editing, my first step in PSE is command-j. That makes a copy of the original. I then click the little 'eye' icon and work only on the copy. Of course, one also needs to save as PSD to keep that original... Only reason to mention this is that you might do this in something like GraphicConverter. I've not kept up with that app since OS X arrived, however, so I know next to nothing about it now. OTOH. I'm not sure it works with 'layers'... much less if its app background has succumbed to the "Black is better" movement!