Hmm, I guess we have some shy GT540 owners
To answer your questions....
No, it is not a theme.
To make your homescreens have this look and feel you will need launcherpro (for a custom dock and dock icons) and desktop visualizer for everything else. Desktop visualizer allows you to place shortcuts on your homescreen and also allows you to give the shortcuts any kind of icons you want, like jpg and png files. So basically you would be able to use a picture as an icon. You can find threads about this all over the forum, specifically the android theme section.
Device: HTC HD2
O.S: Win Phone 7
ROM: XBmod 7.0.7004.0
Device: Samsung Galaxy S
ROM: Stock Gingerbread
Device: LG Optimus GT540
ROM: 2.3.2 SwiftDroid, CyanogenMod 7
Recovery: ClockWork Mod 220.127.116.11