I know I asked this once before but there hadn't been any custom coding that came to light at the time so I thought I'd ask again - has anyone managed to come up with NPC Custom CSS to cover current art with old or custom art in place of the Official?

I assume you're talking about Maleria, in which case give this a try. It appears to work on my end.

.five.column.wide img[src="http://img.subeta.net/maleira.gif"] { padding-top: 300px; width: 293px; height: 0px; background-clip: padding; background-image: url("http://img3.wikia.nocookie.net/__cb20110429012957/subeta/images/a/a9/Maleira.gif"); overflow: hidden;}

(I took the original image from a news comment and I don't know if that link will stay good, might be better to upload to your own host)

edit: Here's your code, hopefully this works e_e

.profile_text {font-size: 11px!important;}

.five.column.wide img[src="http://img.subeta.net/maleira.gif"] { padding-top: 300px; width: 293px; height: 0px; background-clip: padding; background-image: url("http://oi61.tinypic.com/11v663r.jpg"); overflow: hidden;}