The PS3MS default icon bah-lows. I tried using all manner of exe resource editors to change the internally embedded icons but after the program wouldn’t run. Finally I came across this post on the PS3MS forums.
The only thing I’d add is that the instructions only have you change out Play1Hot_256 but there are also resources for 16 and 32 that I changed out. I didn’t leave those as default to see what happened, so if you still have the default small icons that’d be why. Also, the main XMB icon under Video doesn’t preserve alpha.
I’m currently using this icon I found on deviantart.
So far, I have to admit, I’m only using PS3 Media Server to stream .mkv (usually muxed with mkv2vob first. Sometimes .mkv transcodes can have audio sync issues. But next up I’ll look into internet radio, the itunes library integration and web video feeds.