Ok, so I think I have found a few things to help you out..
This is the weapon you would have on your person while patroling your territory.
http://www.youtube.com/watch?v=p4ebtj1jR7c&feature=related
This could be used as a "lawn mower mounted weapon" or LMMW.
[MEDIA=youtube]abTGAP7tG0Y[/MEDIA]
or depending on your budget and size of lawn mower you might consider this option
http://www.youtube.com/watch?v=oATVz5cUJTY&feature=related
and when all else fails...
[MEDIA=youtube]qp6aZIhHiRE[/MEDIA]
