Hallo!

 >>I'm looking for cables to connect a laptop hard drive to the IDE 
 >>controller inside my multia as well as a power source of some kind for it 

 U> What you need is a special connector which has a 44-pin port on one 
 U> end, and a 40-pin EIDE connector and a power cable on the other.  

No, this is exactly NOT what he needs. The multia has (only) a 44-pin notebook
connector on the mainboard, directly below where the notebook hard disk can be
mounted. So he needs a 44 pin to 44 pin cable, of approx. 5 centimeters at
length. This cable is both for data and for power; power comes directly from
the mainboard.

Such a cable is *a lot* harder to get than a cable like you are thinking about.
A hint is to look at Amiga hardware suppliers, because the Amiga 1000 (?) also
needs such a cable to connect IDE harddisks. I got my cable from
www.parts-data.de (click on the Amiga section, they also ship to abroad), but
there are also some resellers in the U.S. that sell such cables.

I would also advise to get antistatic foil or something to put between the
bottom of the hard disk and the metal surface of the hard disk "holder". There
is only about 1 millimeter of distance in between ...

Finally, he will probably have to upgrade the firmware of his Multia for the
ARC or SRM consoles to recognise the IDE controller and allowing him to boot
from the IDE disk.

Regards,
Tobias