This is from the template_6 folder.

Code:
function Particle00_DrawLine_Func()
{
	my.red = 255;
	my.green = 0;
	my.blue = 0;
	my.size = 1;
	my.lifespan = 1;
	my.streak = on;
	my.function = NULL;
}


function Particle00_DrawLine(&start,&end)
{
	vec_diff(temp,end,start);
	effect(Particle00_DrawLine_Func,1,start,temp);
}


Particle00_DrawLine_Func() is the particle and use Particle00_DrawLine(&start,&end) like this:

Code:
Particle00_DrawLine(first_unit.x,second_unit.x);


Notice that my.streak = on, that is a commercial and above flag so if you don't have at least commercial it won't work.

I guess converting quants to feet is up to you like 5 quants to 1 foot or 10 quants to 1 foot, it's up to you.