There wouldn't really be a point of a screenshot. Let me just try to explain this a little better.
I open up WMC on my first monitor and drag it over to my 40" HDTV.
The resolution on my HDTV is obviously full HD, 1920x1080 resolution. BUT, once I MAXIMIZE WMC on my HDTV, the resolution changes to some awful resolution, I'm not sure what exactly. It's not a HD resolution or anything near it.
But, if I window mode WMC, I can drag WMC to make it as big as my HDTV resolution and it'll be fine. Just once I hit maximize, it changes the resolution and I can't get it to HD.