Reddit mentions of StarTech.com 18in Dual Drive Ultra ATA IDE Hard Drive Cable - IDE / EIDE cable - UDMA 66/100 - 40 pin IDC (F) to 40 pin IDC (F) - 1.6 ft - IDE66,Gray

IDE is an old type of data transfer cable. It was replaced by SATA. Its the old "Ribbon cable" http://www.amazon.com/StarTech-com-18-Inch-Drive-Ultra-IDE66/dp/B0000511TN

LOL apparently they're now $5.

Dude that's me at the bottom I was pissed had to wait to get another one. Got this one it worked perfectly StarTech.com 18in Dual Drive Ultra ATA IDE Hard Drive Cable - IDE / EIDE cable - UDMA 66/100 - 40 pin IDC (F) to 40 pin IDC (F) - 1.6 ft - IDE66 https://www.amazon.com/dp/B0000511TN/ref=cm_sw_r_cp_apa_i_iwQSDb892EGAY

Ah, no. I overlooked that. Looking into that now, I see that there's a blue plug on those. What am I plugging that part into, the motherboard, or the old HDD? Or does it not matter?

Well I figured I would check in and post my results for the next guy/gal that comes along googling for a solution while this is all still fresh in my mind. After changing to the SATA to IDE adapter suggested by mikeaton, all of my problems went 'poof'. I must conclude that the Kingwin adapters I originally tried are indeed junk, and I am sure I won't be the last to try these since there is a tutorial out there that is front and center on Google that touts these drives as ones that work (it's why I ordered them originally).

So to summarize: buy this exact one:

https://www.amazon.com/dp/B008X8NK0I/ref=cm_sw_r_cp_api_t0GCzbVHBCMHM

Then buy one of these:

https://www.amazon.com/gp/product/B0000511TN/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Make sure you also have a SATA drive and a molex splitter to power both drives at once

Once you have those, install the new Ribbon cable (to make these work, you will have to install the cable backwards so the blue end that normally plugs into the motherboard is actually plugged into your Xbox HDD: this is just fine and it totally works). You will also have to get creative about how to fold the cable. Mine is crumpled and looks pretty terrible but it works so I am ok with it.

Take your sweet SATA to IDE Adapter, and change the jumper so it's in Slave mode rather than Master. Install your molex power splitter so you can power both the original HDD and the new one at the same time. Boot up your softmodded Xbox, FTP the latest version of Chimp over to your E drive (it seems to specifically need to be run from the apps folder on your E drive rather than the F drive). Don't forget to push over the linuxboot.cfg file to the root of E as well. Then simply swap the ribbon cable from the DVD drive over to your new drive with the Xbox powered up. If XBMC freezes (or whatever dash you have) it probably means your drive is not in Slave mode and is probably set to Master or Cable Select). If you make the swap and things seem to be unaffected, launch Chimp, choose FATX, and away you go! Once you are done cloning, make sure to lock the slave drive to the motherboard. Shut down the Xbox. Take the new HDD and change the jumper back so that it is master. Remove stock HDD and put the new HDD in it's place. Boot and test.

Boom. Home for dinner.

At this point, I suppose you will still want to create your partitions. I used XBPartitioner1.3 (again, just FTP'd it over and ran it from the apps folder on E) and used that to create an F and G drive that basically split up what was left of the 2 TB's evenly between the two. Just read what you are doing and you should be fine.

Big thanks to those that responded with help: I think it speaks a lot about the people here that I didn't get a ton of flack for asking a question and instead got quick (and useful) advice on how to get around the issues I was having. Thank you so much!

StarTech.com 18-Inch Dual Drive Ultra ATA IDE Hard Drive Cable

If you want prime shipping. This is the one I used.