Best practice for multiple version/OS boot?

[Tim Landscheidt]

Hi,

IIRC fedora-review suggested to test packages on all sup-
ported Fedora releases.  So, with a larger hard disk, I want
to install Fedora 19, 20 (soon) and Rawhide and throw in
(recent) Debian and Ubuntu as well.  As my notebook doesn't
support VMs, I'm interested in best practices for partition-
ing and multi-boot setups.

Currently I use a partition for /boot and another for an en-
crypted LVM, so I only need to worry not to put private data
in /boot, and I would like to keep such flexibility.

I suppose I need to create a /boot partition for each ver-
sion/OS.  I have had different Fedora versions share the
same encrypted LVM without problems; I assume Debian and
Ubuntu will do so as well, but I will keep some free space
and partitions just in case.

More contested seems to be the multi-boot setup.
https://bugzilla.redhat.com/show_bug.cgi?id=872826 has a
myriad of opinions on how it should be set up;
http://fedoraproject.org/wiki/User:Jlaska/Multiple_OS_Bootloader_Guide
suggests "chainloader", and
http://www.gnu.org/software/grub/manual/html_node/Multi_002dboot-manual-config.html
recommends "configfile".  Of course there is also GRUB's OS
prober.

So what are Fedora developers /actually/ using?  Creating a
separate GRUB partition and "chainloader"/"configfile"?
Running OS prober in the "main" OS after each installation/
kernel update?  Something else?  How often do the setups al-
low one to shoot oneself in the foot, or are they (more or
less) "foolproof"?

Thanks in advance,
Tim