load balancing ssh

Hi,
any suggestions/pointers what are the best practices in load balancing ssh ?
I googled quite heavy for it and found a lot of general purpose load balancer systems/software
(LVS, balance(NG) , HAProxy) but didn't get too much information how to apply it to ssh.
Im especially interested in the security aspect that a load balancer act's as a "man in the middle" and at the client 
side one gets permanently potential host key changes if the balancer directs to another real host than in the previous 
connection. Are there also other security aspects I should be aware of if I simply use a tool like "balance" to 
multiplex incoming requests on a decicated device to multiple hosts ?
Kind Regards, Leo