Note: *I've only tried this on Msn 7.0.0425 BETA, and not earlier versions of Msn 7*
Well, as we all know about the penguin msn from Rolando for Msn 7, if you overite the skin while it's installed for messenger with the wmp skin it looks really cool, it has the minimalism and the jazz of the two! I think the wmp skin overites the unstable bits and patches them. 
You can do this with any skin, then overite with the media skin but since it's crystalxp I posted the appropriate skin. 
Also I think it looks better with the penguin msn skin anyway.
Screenie:
(Imageshack kept messing up, the link kept braking so the screenie is at my own space Here:
Penguin + Wmp Skin.png
Note: The image is 1024 x 768 px
As you can see:
- There is the cool look of the wmp skin
- All the icons are still the Penguin skin (contact - convo window - msn messenger icon - toast icon - close, minimize, maximize)
- The sign in animation is the Penguin skin
- The toast is the wmp skin with the Penguin skin
- The sign in window has the Penguin skin picture
- The main window is wmp skin
- The convo window is wmp
But after you apply the wmp skin, delete your contact list background image (lvback.gif if I can remember properly) from your normal msn directory, (Usually C:\Program Files\Msn Messenger) or you'll get the TuX with a big white ugly square around it.
Links for download:
- (Sorry I don't have the page before download file for this: I tried, but it came as "error" and the homepage is in a different language) Wmp Skin
- (The other skins like penguin msn ect. Note: These are included as an installer not .rar) rolandunderg.net
I've edited the above post for the image (It's from my space). 
thanks for sharing
