can I install Chimera or Chameleon as UEFI boot device?

Hello,

I have an hard disk with five already installed operating systems (Windows 7, Snow Leopard, three Linux distributions) and plan to install another Mac OS X system on the 13th GUID partition of my disk.

Actually, Mac OS X is on my second partiton where the Chimera bootloader boots using the hybrid MBR entry in BIOS mode.

Can I use any OSx86 bootloader to create an EFI file on the EFI partition for the system that makes it possible to install another Mac OS X beyond the 4th primary partition?

Chameleon is not a uefi bootloader. However, all UEFI boards have compatibility modules that allow them to execute MBR boot loaders. No configuration required, just install chimera on there and roll with it.

I want to use /dev/disk0s13 for the Mac OS X installation. This partition is not accessible in hybrid MBR mode.

Furthermore, the MBR entries must not exist to let Windows boot up in GUID mode. Otherwise starting Windows fails. My goal is to avoid BIOS booting on my system completely.

Is there no other OS X bootloader that saves itself as EFI file on the EFI partition?

To my knowledge you don't need a hybrid MBR at all to boot OSX or Linux. Just a protective 0xEE default.
Avoid hybrid MBRs if possible, they are ugly.
But your hard drive needs boot code (master boot code?)
Grub can boot just about anything, but thats not exactly user-friendly..