[plt-scheme] web server scalability

I found references in the mailing list archieves to memory leaks in
the plt web server, but haven't seen anything in the announcement list
to indicate that they've been fixed.

Can someone please let me know what the current state of the
web-server is in regards to leaking memory (and seg faults)?  I'm
considering scheme for a production system.

Also as an aside, are there any other viable web servers written in scheme? 

thanks.