GraphicRiver iBullz ChalkBoard PSD
Layered PSD | Transparent PNG | 300x600 px | 11.3 Mb

Here is a nice ChalkBoard available in three sizes (small, medium and large) and three styles of colors (dark green, gray and black anodized gloss) and in FULL 16 Bits Resolution. You will meet your requirements, either used for your web design, for an flash concept or UI app. Very easily editable through the import feature of photoshop, you can choose to write add text or drawings you have previously scanner.