Back when I played the Sims 3, I was scrolling MTS (this was about a year after ts4 came out, so not that many people still played ts3) and I found a mod that turned the UI from the boring blue I was used to to a vibrant purple and pink.
http://modthesims.info/d/573785
Do you think anyone will make this for ts4? I think the white is a bit boring.

I'd definitely look after colored UI for Sims 4. I'm trying as much as possible to avoid white ui/sites. (for example, on youtube, facebook and google I'm using dark skins)
I spend a lot of time with my laptop and such bright colors are burning my eyes, sooo yeah, if anyone would recolor sims 4 ui, I'll be first to get it. :S

In S4Studio theres a ton of random images. I could try to find the one for UI