iptraf is so cool, anything like it for disk I/O ?

[Naoki]

Subject says it all..

A cool curses app that can tell you which PID is writing to which file
handle, which is on what device and at what speed.

I've been wondering how to get this sort of info out of existing tools
(lsof, top, etc) without success. 

I guess all the right kernel hooks are there and nothing is stopping me
writing something?