Help for q3demotube Video size/quality

We need the smallest size possible.

Try to get the best size/quality with this 18 sec long movie:
Currently:
- Size: 1,72 MB
- Resolution: 540x260
- FPS: 30
- bitrate: 500k

Output need to be mp4, for streaming purpuses with JW Player
http://code.jeroenwijering.com/trac/wiki/FlashFormats

Current command looks like this:
ffmpeg.exe -y -r 30 -i "11-videos/14.%010d.jpg" -i "11-videos/14.wav" -r 30 -acodec libfaac -ab 128k -vcodec libx264 -s 540x260 -b 500k -maxrate 100k "14.mp4"

Media link: http://own3d.at/tmp/11-videos.rar