Can we not just name the XSI theme something else a little more vague like suggested? It’s a great theme. I’ve barely used XSI, so I don’t know exactly how close the Blender’s interface looks once the theme is loaded, but it’s not like Blender is magically transformed into XSI and I don’t think users of 3ds Max or Modo are going to feel left out especially with a name change.
I think it would be a great nod to one of the most influential pieces of software made by one of the most influential companies in the industry…both dishonorably dissolved by a greedy giant. It’s also just a great looking theme.