Part of my 1/144 scale spacecraft collection, the L4200 is a hypothetical space plane developed by Lockheed Martin and Orbital Science Corporation as a competitor to Boeing's family of space planes (Leviathan
). It is based on the idea of a manned, upscaled X-34 that incorporates tech from the Orion and the X-33. (Likewise, the CST-250/350 were derived from X-37B and Space Shuttle tech). It is also featured in an original short story "To the Moon, Mars, and Beyond".
The model itself was a repaint (with rattle-can) of the X-34 available at Jon Leslie's site.