I have been trying some Linux distributions as: Ubuntu, Xubuntu, Trisquel and Linux Lite.
As all of them are Ubuntu and flavours if you want to boot any of them from an Iso located in Isos folder on your HDD, you can use grubfordos and the following config in your menu.lst (you just need to addapt it according to each distro, to see the content of preseed folder in Iso file of each one it is better to use 7zip):
Thanks to Steve6375 for this menu, this is part of my menu.lst:
title ubuntu-14.04.3-desktop-amd64.iso\nubuntu-14.04.3-desktop-amd64.iso desde HDD
##ISO file must be contiguous on disk in this case, use Wincontig
set ISOSCAN=/Isos/ubuntu-14.04.3-desktop-amd64.iso
find --set-root %ISOSCAN%
map %ISOSCAN% (0xFF)
map --hook
root (0xff)
set try=/casper/vmlinuz
if exist %try% set kernel=%try%
set try=/casper/vmlinuz.efi
if exist %try% set kernel=%try%
set try=/casper/vmlinux.efi
if exist %try% set kernel=%try%
set try=/casper/initrd.lz
if exist %try% set initrd=%try%
echo kernel %kernel% file=/cdrom/preseed/ubuntu.seed noprompt boot=casper iso-scan/filename=%ISOSCAN% locale=en_US.UTF-8 splash -- > (md)0x220+1
echo initrd %initrd% >> (md)0x220+1
configfile (md)0x220+1
title xubuntu-14.04.3-desktop-amd64.iso\nxubuntu-14.04.3-desktop-amd64.iso desde HDD
##ISO file must be contiguous on disk in this case, use Wincontig
set ISOSCAN=/Isos/xubuntu-14.04.3-desktop-amd64.iso
find --set-root %ISOSCAN%
map %ISOSCAN% (0xFF)
map --hook
root (0xff)
set try=/casper/vmlinuz
if exist %try% set kernel=%try%
set try=/casper/vmlinuz.efi
if exist %try% set kernel=%try%
set try=/casper/vmlinux.efi
if exist %try% set kernel=%try%
set try=/casper/initrd.lz
if exist %try% set initrd=%try%
echo kernel %kernel% file=/cdrom/preseed/xubuntu.seed noprompt boot=casper iso-scan/filename=%ISOSCAN% locale=en_US.UTF-8 splash -- > (md)0x220+1
echo initrd %initrd% >> (md)0x220+1
configfile (md)0x220+1
In red is all you need to change according to each distro you want to test, open the Iso with 7zip to see the name used for *.seed file in preseed folder.
Another way is try it from a multiboot USB 2.0 made using Yumi, it extracts the content of the Isos (using 7zip) in a folder for each one of them, it uses syslinux as boot loader, creates a multiboot menu and let you add a reserved space for keep the changes (If you make some) when you boot the distro, it is also capable to boot WinPE Iso's (using a very old grubfordos v0.46a, but it works). Also from this multiboot USB you can install to a partition on HDD any of this distros after you boot from the distro (this can't be done if you are booting from an Iso on your HDD), better don't try this if you are not an advanced user.
I'm writing this from Linux Lite installed on the third logical partition of my HDD, this OS is very compact and fast but has LibreOffice 5.0.1.2 and some other good applications preinstaled as Safety Copies and Lite Tricks, and some other you can download from it's own site and also from Ubutu too. It's menu looks like a Windows start menu.
Best Regards
alacran