Code:
making type 6 a cylinder or sphere or something
But the idea of Steffen sounds good to me. One question that needs to be answered is "Are files with lines 6 (or above) readable by current tools?".
Edit:
MLCad - "Error in line, should file be loaded" and the line is deleted if you proceed and save.
LDView - "Error parsing line" no effect on visual result
DATHeader - "Error using 0 comment" - strange error message. Correction of that line do not work, so it stays