I adapted modern optical mouse for standard Amiga port. The author of this idea StarCat from amiga.org.ru forum. He described it verbally, but I decided to solder in reality. The advantages of optics to mechanics obvious. It doesn't require any adapter, plug'n'play 
You can watch a short video on You Tube (including English subtitles).
If you are (non)interested in this topic - let me know.
I did the same thing with the 800dpi genius optical mouse only i installed the pic in the DE9 housing, so its all self contained and no adapters needed, i used the project on aminet to program the pic chip.
