Linking zoom to altitude?

Just an idea, but is there a gauge/utility in existance that can make the main (2D cockpit) view zoom out smoothly with increasing altitude?The point would be that on approach / ground I like to set something like 67% zoom but the whole experience looks much nicer up high when zoomed out to say 40%... A gauge that made this change in the background would be really neat... Probably it would simply set the zoom according to a table in an ini file or similar. Anyone heard of such a thing?Cheers,Geoff