ah - i never look at those pesky locations... its an american thing.
I cannot imagine however that you could not locate a local / regional sign shop that could give you the name of their plotter blade supplier. If your that remote I'm wondering how your gonna get the rest of the parts for a CNC machine
E-Stop is correct in that the knife must be floating to cut into the direction of the plot. Swivel knives are rather common for pattern cutting so I am sure we can track down something close enough to you.
http://www.a2zhobbies.com/Xacto/Knives/XAC-3241.html
Keep in mind - the only time I have seen this rigged up - it didnt work all that hot, but I'm used to our production machine - might work great for your needs.