I wonder if you'd be happy compartmentalizing your .LIN file by simply separating your chunks of line definitions visually.
Example:
;;
;; AUTOCAD DEFAULT LINETYPES
;;
*BORDER,Border __ __ . __ __ . __ __ . __ __ . __ __ .
A,.5,-.25,.5,-.25,0,-.25
*CENTER,Center ____ _ ____ _ ____ _ ____ _ ____ _ ____
A,1.25,-.25,.25,-.25
*DIVIDE,Divide ____ . . ____ . . ____ . . ____ . . ____
A,.5,-.25,0,-.25,0,-.25
;; Complex linetypes
;;
;; Complex linetypes have been added to this file.
;; These linetypes were defined in LTYPESHP.LIN in
;; Release 13, and are incorporated in ACAD.LIN in
;; Release 14.
;;
;; These linetype definitions use LTYPESHP.SHX.
;;
*FENCELINE1,Fenceline circle ----0-----0----0-----0----0-----0--
A,.25,-.1,[BOX,ltypeshp.shx,x=-.1,s=.1],-.1,1
*BATTING,Batting SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS
A,.0001,-.1,[BAT,ltypeshp.shx,x=-.1,s=.1],-.2,[BAT,ltypeshp.shx,r=180,x=.1,s=.1],-.1
*ZIGZAG,Zig zag /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
A,.0001,-.2,[ZIG,ltypeshp.shx,x=-.2,s=.2],-.4,[ZIG,ltypeshp.shx,r=180,x=.2,s=.2],-.2
;; Company Defined Linetypes
;;
;; The following linetypes are company custom definitions, consult KrusherT before messing with it under pain of tar-and-feathering.
;;
*KRUSHTYPE,Krusher's LINE -----KRUSHERT--------KRUSHERT------
A,.5,-.2,["KRUSHERT",STANDARD,S=.1,R=0.0,X=-0.1,Y=-.05],-.25
Having different sections for each 'category' of linetypes, in that case, ACAD default lines, Complex lines, and company custom lines.
If that's not cool, I understand. Just food for thought, in case you haven't already tried it. I'm OCD about organization as well, most of the time.