SLX is the nearest modern equivalent, but that's 10 speed, and nothing is compatible with 7 speed (except the freehub with appropriate spacer), so you would have to upgrade everything at the same time.

What parts are wearing out? you can still get, pulley/jockey wheels, bottom brackets (UN54/55) chains, 7 speed cassettes & chain rings although the cassettes and chainrings may be harder to find at LX level., the only hard to find part will be shifters.