I used to own one of those very same T-Shirts - the "Electric Blue Superman logo," on a black T-Shirt.
As much as I didn't like the story or the idea or Jurgens et al, I thought it was a very cool-looking S design.
Sorry to say, my shirt didn't survive and now you've got me thinking about a replacement. I've looked at the graphitti designs site and at ebay and at emerchandise and at the superman superstore, and I can't find it for sale anywhere.
One might be able to dig up an old un-opened one at a big shop (like forbidden planet) or at a convention.
Your husband might have an ultra-rare collectors item!