There is no room to put an "Elite" line. The closest thing they have would be the line at the far left, which is used to screen those selected for additional screening ("SSSS"), and also used by vendors to screen crates of sodas, water, beer, etc.
There is a plan to redo all the LGA terminals, starting with tearing down AA's hangar next to Terminal D, and making that a Terminal. Then redoing Terminal D, C, etc. Cannot remember the timeframe, but it would have to be a least a decade (if ever) before you see anything new at LGA.