Well, actually, you can do it with cylinders. I'll explain:
First of all, create a cylinder with size 100 and texture/colour/ghost/whatever it. Now, position it in the centre of the two objects - you'd use a basic (xpos_1# + xpos_2#) / 2.0 for each of x, y and z to get this. Now, use the point command and point the cylinder towards one of the objects, it doesn't matter which.
Then comes the trickier part - you need to calculate the distance. Because I'm such a generous guy, here's a distance function that I've written that'll save you from having to figure it out yourself:
function CALC_Distance(x1#,y1#,z1#,x2#,y2#,z2#)
endfunction sqrt(((x1#-x2#)^2)+((y1#-y2#)^2)+((z1#-z2#)^2))
It's probably a good idea for you to try to figure out what it does; it's really just two instances of Pythagoras calculations - one to find a 2D distance in the X and Z axis, and then another to calculate a 3D distance by using this value and the Y axis.
Anyway, once you've got the distance, it's time to do some scaling! Set the scaling of the cylinder to X=1, Y=Distance and Z=1. This will make the cylinder very tall and thin, although you might like to fiddle with the two 1's until you get a thickness that you like.
Hope this helps!
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