In no particular order. These are things you might want to investigate for yourself. A listing here should not be taken as an endorsement. In fact, in many case I have not used the product and cannot comment on it.
Network-booting Your Operating System describes several techniques for booting across a network, using grub and some other tricks. I haven't tried it, but I have a sneaky suspicion that with an especially trained floppy diskette, you could get your entire first stage image onto the computer to be restored.
"Smart Boot Manager (SBM) is an OS independent and full-featured boot manager with an easy-to-use user interface. There are some screen shots available." It is essential if your BIOS will not allow you to boot to CD-ROM and you want to use a CD-ROM based Linux for Stage 1 recovery.
W. Curtis Preston's excellent Unix Backup & Recovery. This is the book that got me started on this bare metal recovery stuff. I highly recommend it; read my review. However, you should probably get the latest edition.
tomsrtbt, "The most Linux on 1 floppy disk." Tom also has links to other small disties.
The Linux Documentation Project. See particularly the "LILO, Linux Crash Rescue HOW-TO."
The Free Software Foundation's parted for editing (enlarging, shrinking, moving) partitions.
QtParted looks to do the same thing with a GUI front end.
Partition Image for backing up partitions.
From the web page: "Partition Image is a Linux/UNIX utility which saves partitions in many formats (see below) to an image file. The image file can be compressed in the GZIP/BZIP2 formats to save disk space, and split into multiple files to be copied on removable floppies (ZIP for example), .... The partition can be saved across the network since version 0.6.0."
Bacula is a GLPled backup product which has bare metal recovery code inspired in part by this HOWTO.
"g4u ('ghost for unix') is a NetBSD-based bootfloppy/CD-ROM that allows easy cloning of PC harddisks to deploy a common setup on a number of PCs using FTP. The floppy/CD offers two functions. First is to upload the compressed image of a local harddisk to a FTP server. Other is to restore that image via FTP, uncompress it and write it back to disk; network configuration is fetched via DHCP. As the harddisk is processed as a image, any filesystem and operating system can be deployed using g4u."
"We present Frisbee, a system for saving, transferring, and installing entire disk images, whose goals are speed and scalability in a LAN environment. Among the techniques Frisbee uses are an appropriately-adapted method of filesystem-aware compression, a custom application-level reliable multicast protocol, and flexible application-level framing. This design results in a system which can rapidly and reliably distribute a disk image to many clients simultaneously. For example, Frisbee can write a total of 50 gigabytes of data to 80 disks in 34 seconds on commodity PC hardware. We describe Frisbee's design and implementation, review important design decisions, and evaluate its performance."
There are a number of USB key disties available. Check DistroWatch for details.
CD-ROM based rescue kits. This is not intended to be an exhaustive list. If you know of one (or even something that pretends to be one), please let me know. You may find more recent information at DistroWatch.
Mondo Rescue "... creates one or more bootable Rescue CD's (or tape+floppies) containing some or all of your filesystem. In the event of catastrophic data loss, you will be able to restore from bare metal."
"Cool Linux CD is live CD with Linux system. This used 2.4 kernel and some free and demo soft."
SystemRescueCd" is a linux system on a bootable cdrom for repairing your system and your data after a crash. It also aims to provide an easy way to carry out admin tasks on your computer, such as creating and editing the partitions of the hard disk. It contains a lot of system utilities (parted, partimage, fstools, ...) and basic ones (editors, midnight commander, network tools). It aims to be very easy to use: just boot from the cdrom, and you can do everything. The kernel of the system supports most important file systems (ext2/ext3, reiserfs, xfs, jfs, vfat, ntfs, iso9660), and network ones (samba and NFS)."
Syslinux builds boot code for floppy diskettes, CD-ROMs and Intel PXE (Pre-Execution Environment) images. It is not dependent on a floppy diskette image. You can build your own CDs with a number of tools, such as tomsrtbt, on it.
In case you'd like to roll your own: "Linux Live is a set of bash scripts which allows you to create [your] own LiveCD from every Linux distribution. Just install your favourite distro, remove all unnecessary files (for example man pages and all other files which are not important for you) and then download and run these scripts."
"The PPART CD allows you to generate system recovery bootable CD of previously saved hard disks."
Timo's Rescue CD Set: " This set is my approach for an easy way to generate a rescue system on a bootable cd, which can easily be adapted to the own needs. The project evolves more and more into a 'debian on cd' project, so it's not only possible to use the system as a rescuecd, it is also possible to install a whole debian system on cd."
The List of Live CDs has more CD based disties.