Good things come to those who wait!! I am happy to announce that I am now an owner of a Contax mount IQ180 after what seems like an eternity of searching!! Holy shit that took forever, and it was a lot of back and forth with people. Here are the scenarios I encountered along the way (may be helpful for anyone that is looking to price out their own purchase in the future):
1.) "Mr. S" - Mr. S has an amazing camera collection, and I actually really enjoyed talking to this person. Said that they would be willing to sell, but I could tell they weren't really ready to part with it. Initially wanted 10K for it, but later wanted 12K. Kind of glad I didn't buy this one, because now I feel like I'm in their 'club', and I can call them for advice and whatnot.
2.) "Mr. V" - I thought this was it. I found this person by searching all of the IQ180 hashtags on IG and FB. This was the only person that was using a contax mount version. I messaged them last May (knowing wedding photography gigs were drying up due to COVID), to see if they wanted to get rid of it. They sent me a bunch of photos of the kit, the case... everything, and he only had like 2K actuations on the back, it was in really good condition. He wanted to sell it for 11K (they still owed money on the back, because they purchased from a dealer). I was hoping to spend 10K max, but I actually agreed to the 11K. Radio silence. Two weeks later he messages me saying isn't going to sell it because his wife wants him to keep it.
3.) "Mr. W" - This one was relatively recent. End of February. I had completely given up on a 180, and decided that I would look for a 160, or 260 (I like CCD sensors, so I would NEVER consider buying a 150 or any of the CMOS backs). I had a message in my inbox from someone who was selling a IQ260 in really good condition, for 10K. I thought that it was a bit high, but I wanted to end my search, so I entertained the offer. Also, I was looking at the differences between the 1 and 2 series, and I know this is petty, but the tiny bump in DR was something that was appealing. So, I loaded my account with 10K getting it ready to send off, but then...
4.) "Mr. L" - ...I got an ebay alert for a new listing (I have every possible Iq180 phrase imaginable set on my phone). The alert was for a P65+. I looked at the listing, and noticed that the seller mentioned that they also had an IQ180 in the description, and that they would be listing that one soon. I talk to Mr. S every once in a while, and they told me that I shouldn't settle on a 160 or a 260, so I was kind of hesitant in sending the payment out to Mr. W. I told Mr. W that I would like to see what will happen with the IQ180 listing, and if it didn't go well, I would purchase his 260. Well... he didn't like that very much, because I never heard from him again! I DM'ed Mr. L, and did a little google investigating (using his ebay username to see if there were any photographers with similar names in the area he was listing from to determine if this was a legit listing - ebay has a LOT of scam auctions that pop up on a very regular basis). Mr. L was legit, and so I asked him what he wanted to sell it for. We eventually continued the convo outside of eBay by phone. Very nice guy, and legit. He even had a lot of accessories that I wanted to add to my kit. I ended up buying this from him directly, and it arrived at my parents' house today (I'm not in the US right now, and Mr. L only wanted to send it if someone could sign for the package in the US). In total I spent less than 8K for the back, all of the extension tubes, the battery pack grip, a bunch of batteries, the 140mm lens, and a lot of other accessories that I've been wanting to get (Mr. L is switching bodies). For those searching, I would not use my price point as reference point, as I'm sure that I was quite lucky.
There were a few other people, but a lot were scams. One of the scammers was hilarious. I knew it was a scam immediately when they told me they were from Montana but their English was obviously not at native-level, but decided to drag the conversation out to see how far I could take it. I told him to send me a photo of the DB with his name and today's date written on paper, and he sent me the shitty Photoshopped picture that I've attached to this post. I was so confused. I thought to myself, "You realize I'm a photographer, right? How in the burning, hot hell were you planning on trying to trick me with this garbage?" I will say that most of the scammers came from FM's forum. However, there are a lot of really good listings there too (I bought my C645 body + 80mm lens from there). Just gotta be careful.
Anyways, that's the SHORT version of what it took for me to get mine. Thank you guys for all of the assistance throughout the years. I'm ready to use this and hopefully put it to work ASAP!! I think that's it for rare purchases for me for a while.