I thought you might render a snapshot of each few chunks from maybe 16 angles and compose them together like backdrop pieces on a stage. Update the snapshot every time a player moves over that chunk. Just patch into the render function: are we within the (basegame settings) chunk draw distance? (yes) - render the chunk - (no) - retrieve the "backdrop piece" for that chunk from this view angle, and draw it behind everything else rendered so far.

You could even add atmospheric effects to cheat and only save a monochrome image, then tint it progressively bluer and bluer (but not invisible) with distance.