If you have MS-Word you can import a clip art image into word then cut or copy the image.Inside autocad select edit, paste special , insert as autocad entities. this will convert the clipart files into pure dwg files.
You can possibly find a lot of 'people' on the 3D animation sites. (for lightwave, maya, and programs like that). Some of them are in DXF format, although also a lot of them are dressed as space rangers and so on. Which might be a good thing?