any of the 8speed barcons available new are the one with the compat pull ratio. there were very old DA-only 8speed shimano barcons, but they're scarce these days. Any shimano barcons will work in friction mode.

While many retailers will call the various barcons "ultegra" or "dura-ace" shimano considers them non-series items. Only the very old 8 speeds from the 90s will be incompat with your lx.

-rob

ps-jenson has them, dirt cheap.