HTTP load balancing options

We are currently using pound (http://www.apsis.ch/pound/) in front of 5
IIS (ew) servers and while it works well one thing I have been
requested to find is an HTTP load balancer that can send more sessions
to servers with lower response times, instead of just doing straight
round robin or weighted round robin balancing.
For example if web3 is responing in 0.26 seconds and web1 is responding
in 0.10 seconds, the next new incoming connection would go to web1.
All connections MUST be tracked with a cookie, so straight layer 4
switch/balancing isn't going to be "good enough".

I have been googling and checking freshmeat but I haven't been able to
find a solution or combination of solutions that does what I mention
above. Any suggestions are appreciated.

thanks,
bdm

--
kernel panic: signature not found

Try a shell script that checks for each servers response, and create a
netfilter rule that would represent the values.

http://linuxgazette.net/108/odonovan.html

Hope this helps
jason