Okay, since the other thread is getting pretty full I continue here.
tbuitenh suggested offering an option to enable not installing Lilo, since currently it is installed to MBR.
I think an option would be offering a 3-way-option, probably defaulting to the current behavior, installing Lilo to the MBR of the hard-drive.
The options would be installing to MBR, to the partition-bootsector or not at all (which would result in the installation not being bootable without help).
As far as I understand a partition has to be marked active to be bootable. I just tried this in one of my images and, by using fdisk to do so, killed that installation.
Right now I'm copying another install and will try it with parted.
So far I don't know if installing Lilo to the partition-bootsector will work with encrypted partitions and LVM. My previous try was with an encrypted partition and afterwards the LUKS-header was gone, which might be a result of changing this flag, or of using fdisk. I suspect the latter at this time.
Anyway, my next try will be with LVM, installing it to the partition that holds the LVM, since installing it to the logical volume wouldn't make much sense, the BIOS can't access it anyway.