DreamTree, what you suggest may work, or may not. Or maybe, you can make it work with little effort.
The root of the question is in the details of HOW the RAID system in that external Iomega case writes its data to the drives. Any drive system must, as the very first step, write to a HDD unit two key things known as the MBR and Partition Table. All BIOS systems look on a HDD for those pieces of info in a fixed place at the start of the drive. THE MBR basically is a small bit of code that can read the very first data from the drive. It really is a loader for a larger machine-language routine that actually does load and read the rest of the disk, according to the OS installed. The Partition Table contains details of exactly how the available space on this HDD hardware unit is allocated (in contiguous blocks) to Partitions that each will be treated as one logical "drive". Now, some RAID systems write these in such a way that any other common OS like Windows can read those two and understand them enough to start the loading process and get a basic boot into the OS going. Some, however, write slightly different data in places and Windows cannot use them to boot from.
In almost all RAID1 systems there is a way to un-RAID the drives. Now, on the drives ALMOST everything is identical between the two units, except for a few small details in those MBR and Partition Table records. The simplest way that a RAID1 system can "Break" an array into stand-alone individual drives is to re-write those few items in a way that Windows or any other OS can understand. Thus BOTH drives become perfectly good usable drives - they just happen to be complete copies of each other. And hence, they can be used anywhere with all their data. HOWEVER, if that operation to "Break" the RAID1 array is NOT done first and you take one HDD unit and try to use it as a stand-alone unit, that may not work, depending on the details of how that particular RAID1 system writes its info at the beginning of each of its member units. So, it night work, and it might not.
There is another way this can be done in most cases. We are talking about what happens when the Iomega 2-disk RAID1 enclosure fails because some part of the enclosure (e.g., the RAID controller, or the power supply, etc.) failed but left the disks unharmed with good data. By far the simplest first step would be to go to Iomega and ask them to supply either a replacement identical drive case, or a newer unit that uses the SAME RIAD1 algorithms and hence can read those drives with no trouble. With a long-standing company like Iomega I would expect them to be able to do this. BUT I suggest you inquire carefully about that possibility BEFORE you decide which external RAID box to buy. And, of course, you should also ask whether that would be completely unnecessary. IF their way of running the RAID1 array is such that you actually CAN simply take one drive unit out of the case, plug it into a computer as a normal stand-alone drive and use it right away with NO special step to "Break" the array first, then you will not have a problem.