While I agree there is no systematic ranking/rating (i.e. visible for cabin crew etc.), there is certainly one "behind the scene". Last year LX had their Euro08 lounge in Zurich, to which they invited HONs, SENs and occasionally also FTLs. It was discussed in this forum.

Now, I got an invitation to the C-class section of the lounge only at short notice (3 days) and for a low interest games. Other SEN's got their invitations much earlier, to better games and sometimes even to the F section. I explain this because I'm really not a frequent LX flyer, I make less than 10 percent of my miles on LX. Totally acceptable for me - but they need some additional information, more than just the status.