I have been hunting this manual down for quite a long time. And today I have found and bought myself a copy for under $100.
I thought you’d be interested too: BMW 5 series BENTLEY E39 Service Repair Manual

Here is search I did and it looks like there are few books for good prices there

Update: “adjmcloon” on bimmerfest forum just let me know that the same book is on sale from Bimmerzone for about $107 with FREE shipping. Also make sure to check out BIMMERZONE ebay store