Get in touch with low latency people from Sun, IBM or RedHat? 
whenry: Consider looking at Red Hat MRG's realtime offering. Red Hat have done work with both IBM's and Sun's realtime JVMs.http://www.redhat.com/mrg/realtime/
http://www.redhat.com/mrg/faq/It's geared towards low latency.
Let me know if I can help more.