zOLD,
On the Lombard, you cannot boot to a USB HD running 9.x (no 10.x) while the Pismo and later can do so.
It is also not possible to boot any HD or optical device through a FireWire or USB PC card since these cards do not have the firmware to initialize at startup. I do have an MCE Transport PC Card HD which will boot 9.x (but not 10.x) on my Wallstreet. I recall that when the Lombard was released, the PCMCIA card slot no longer supported this feature; this was probably due to the New World ROM. The bottom line is probably this: The Lombard's PCMCIA/CardBus slot will not boot through any PC card.
You can connect the Lombard to another Mac with SCSI port by using SCSI Disk Mode. The Lombard also has another limitation: You must have a functioning OS on the HD for SCSI Disk Mode to work, again due to the New World ROM.
http://docs.info.apple.com/article.html?artnum=13611
You can, however, boot to a SCSI HD.
Another option is to consider
MCE's Media Bay HD Enclosure. Just place your internal HD into this enclosure, slip it into the media bay and use it as a regular HD. You will want to call MCE to see if this device is supported by OSX.
