The Videum frame grabber card requires both +5V and +12V power supplies to function. Some embedded systems run only on +5V and do not have a +12V supply. If this is the case, you may wish to look into the PowerTrends PT5041A ISR (Digi-Key part number PT5041A-ND), which can provide a +12V 1A output from a +5V source. Any +5V to +12V ISR will probably do, but I have had good success with PowerTrends ISRs.
Check the technical specifications of any other ISA grabber card you may be considering; it may also require -5V and -12V supplies. You can make a quick (though not always accurate) check for the voltages required by an ISA card by looking at conductors B3, B29, and D16 (+5V), B5 (-5V), B7 (-12V) and B9 (+12V). If the conductor on the card edge doesn't seem to have a trace going anywhere, it is probably not used.
You can further slim down the adaptor described in this article by changing the pin mapping and plugging the female IDC sockets into the bottom of the PC/104 card instead of into the top, as I describe. You will need to remap the pin connections, but this may work better for you.
An 8-bit ISA adaptor (lacks the C and D signals) can be constructed even easier. Just make exactly the same adaptor, but leave out the C and D sections. You can even crimp a 64 position cardedge connector onto the ribbon cable to accommodate your 8-bit ISA card for a truly simple solution. Just remember that the last pair of contacts in the slot are unused. The slot will be bigger than your 8-bit card by this extra pair of contacts. Remember not to plug the card in backward nor plug it into the extra contacts.
The 64 and 40 conductor ribbons can be further separated into smaller groups of five or more. It looks messier, but it eases the folding of the cables if you need to fit the card into a limited space or position.
You can buy ISA to PC/104 adaptors, but they are typically bulky and sometimes expensive. They will do the trick, however. I have listed some sources for commercial adaptors in the Resources section.
The BT848 (Brooktree) frame grabber is probably the single most supported frame grabber in Linux. I used the Videum card, but you may wish to spend some time tracking down an ISA BT848 card (if they exist).