Wow, nice thread!
One thing that I was always wondering about since I started collecting is how rare any model can be. I mean there must have been so many of each model...even if it was only built for a short time.
The rareness we experience is mostly based on where we live I think. Many models were only sold in certain parts of the world, for example the BomBeat 40 in South America or all those domestic Japanese ones.
The next question is how many survived until today. After seeing the quality of a DiscoLite I was very surprised how relatively common it still is to find them in good to very good condition.
One thing I would add as well is the rareness of certain models in good condition. I remember having a very beaten up Sanyo 920 and it was a bitter sweet experience. So it is definitely harder to find something in accpetable condition making a near mint box more rare too.
Of course I have to mention stuff like the VZ-V20R or the MR-X20S, two models I am still looking for too.
For now, I'll leave my personal list here:
5. BomBeat 40
It's probably not as rare as it used to be since a few popped up last year but it is still quite hard to find and probably impossible without a bit of luck.
4. Victor RC-M70GX
Out of all the M70 variation I think this is the rarest and most special one. I wish JVC would give out more information about it...I would assume that it was some kind of anniversary edition of the successful M70 series. I have spotted two or three in Japan and got mine from Russia.
3. JVC RC-550LM
Even though I ended up with four of those in total for some reason (still have two right now) they are one rare box and I have seen only two until last year. I traded an M90 for my first one and don't regret it at all. Those silver blocks are so special and there are probably less than 15 around in the collecting scene.
2. Conion C-100F Gold Edition
Now that one is rare, hands down. I didn't pay as much for any other box as I paid for this one but it was worth every penny. The golden finish looks amazing and it is fully working and 100% complete. I really do not know how many of them are out there but I guess there is only a few left in complete condition.
1. ITT RC-8800
Funny enough, I believe this is actually the rarest box in my entire collection. this ITT labelled BigBen is one of two I have seen since I started collecting and Google does not show any info about it. Fun Fact: The tuning scale still has M-X960K printed on it...I guess it was an issue for the German market and ITT ordered a couple of them in this configuration.