I know that!...
I have 5 iso (DamnSmall linux, Flonix, Knoppixmame, LuitLinux and Womp)... Thay are live-cd... You boot with the cd and the OS is loaded in memory...

All the iso make a size of 410 MB... So it's ok...

Reference:

knoppix

So you want to combine all of the live-cds to make one with a menu to choose between them? I'm not sure if grub/lilo can do that. The previous posts were on just putting grub on a cd then booting from the hd. You may be able to with something else.

Copy the files from the isos and make a big iso out of those. The menu part will be difficult. Make sure the files are in the same place.

How live-cds boot:
A bootable cd just has a copy of a bootable floppy on it (and is configured in a certain way, see above). The floppy image has a small kernel and initrd (initialization ramdisk) on it. The kernel boots, and loads the initrd as it's filesystem. The initrd tells the kernel what to do next (maybe setup the cd-based Linux).

Each of the distros has it's own floppy image file that it boots from. Take note of them. Don't be confused by floppy image files that aren't being booted from, as their may be some. Then, customize your own floppy to choose from these floppy images. Use your custom image to make the bootable cd. See this:
http://www.linuxgazette.com/issue85/sipos.html

Putting a bunch of rescue cds onto one cdrom where they can be selected from a menu could easily fall under the category of
If you want to pursue it anyway, do a google for bootscriptor

thank!...
I willt try to do that.... When i have some results y will write again

Well, I couldn't resist. I googled around and came up with http://www.ultimatebootcd.com/ . This cdrom is really cool and already has a couple of small linuxes on it like freesco, tomsrtb and trinux. Man this cdrom has a lot of neat stuff on it!!
Anywho, there is also a link which shows you how to add knoppix. That of course would have to be one of the chopped down remastered versions of knoppix. I put Feather Linux V0.3.7 on to try it out. Works like a charm.
http://www.sadyc.net/UBCD_Knoppix.html

I haven't quite figured out how to get the other distros on the cdrom. Like BBC, Blin, Puppy..... or any of the small ones. There is room on the cd as the original package is about 160M if I recall but the procedure is a bit different.