> - /etc/init.d/vserver-default cannot be added by "chkconfig --add"
>   because the corresponding line in the script is contains "-"

won't change that; 'chkconfig --add' registers the script for SysV init
only and it works with '-'.  But '-' prevents the script from being
started without prior activation. Such an activation is something like

| chkconfig vserver-default on

IMO, it is not a good (and insecure) style when services are activating
themself (s!-!345! would be such an activation) for automatic startup

> - /var/lib/run/vservers.rev seems to never be cleaned of its symlinks.

should happen upon reboot by your distribution; but util-vserver works
fine with dangling symlinks also

> - When I stop a vserver on some hosts, I get this message :
> # vserver foo stop
> /usr/lib/util-vserver/vserver.stop: line 85: 9287 Killed "${NICE_CMD[@]}" ...

it is difficultly to diagnose this without more details; but I
suspect that a process did not terminate and was killed by the
external vwait. .209 will contains some more diagnostic for this
case

> - When stopping a vserver, in addition to the strange message cited
>   just above, I noticed that the corresponding IP alias is still up
>   and running, answering to pings, etc... Is it a correct behaviour
>   ?

IPs should be cleaned up, but sometimes, it is complicated to complete
tasks when previous actions failed; please try if it still happens
with .209 (which should appear this weekend) and reopen the bug when
needed