To bump a slightly old thread, along with the usual ATV's, how about the lower powered off-road capable type smaller motorcycles - to scale to the size of the fields that most of us play on. Most playing fields, face it - a 500cc military Armstrong, or 650cc militarized KLR650 would be WAY overkill considering the distances needed to be covered on 'scout missions'.
I'm thinking on lines of this:
Honda CT70 - 72cc 4-stroke MiniTrail
or this:
Honda Ruckus/Zoomer - 49cc 4-stroke Util-Scooter
set up a pintle mount on/between the handlebars for carrying your personal weapon, and you are good to go.
Basically, my reasoning is that these are the sort of modernish counterparts that come close to the WW2 Commando Corgi/Welbike in terms of design purpose.
I confess that i do have an ulterior motive to asking about this, since i do have a few basket-project CT70's sitting in the back of the garage waiting for motivation, inspiration, and purpose.. It'd be a heck of a way to combine my two favorite past-times..