How are your LISP abilities?
Could draw the line, use a selection set 'window' with a small aperture centred on the start point to grab all the entities at the start point. Remove the new line from the selection set and with luck you'll be left with just one.. which you can get the layer from with (assoc 8 -EntityDescription- ) and apply that to 'entlast' - the line you just drew. Lisp could be a whole lisp including draw line or could be modify the line after it has been drawn (though use format painter would be just as easy in that case)
I don't have something to copy and paste though