I am going to answer my own questions
1. I do think the rarity of a smurf depends on where you are located. For American collectors a lot of promos are pretty much unattainable and we probably are willing to spend a lot of more money on i.e. a Jubilee smurf than other collectors. This fact was brought home to me on my last visit to Germany when I found Jubilees for around 5 euros at a fleamarket (and they were the higher prices smurfs). I have spent way more than that for my other Jubilees that I bought on US ebay. I was also told that the Silan smurfs and other promos are really not rare in Europe, but over here you can see them go for high prices.
This works as well the other way round: In the US the four applause super smurfs aren't really superdouper rare and I was surprised when I was able to trade mine in for some smurfs that were pretty much unattainable for me otherwise. The same is true with the Kinder egg smurfs. You hardly ever see them (especially the monoblocs) on US ebay but on German ebay they are as common as sand on the beach. Are they rare smurfs..not really but much harder for me to get and more expensive as well..so I really think a lot depends on location.
2. yes, there are many smurfs I dont' think I will ever own and I don't even actively pursue them although I have been proven wrong and now own quite a few of them. (I have to say I got them from seller (s) I 100% trust and they aren't full time sellers either)
3. I personally haven't really gone into the "one of a kind" or rare color variations because I have no way of holding the smurf in my hands before buying it, nor would I even be able to tell if it is an original product or not. To say that a lot of the sellers with their own coloring line at home have kind of spoiled this for me would be an understatement. It really has come to that I won't believe a seller to tell me the truth, nor would I trust myself to know the truth. I do know that a lot of collectors have the opportunity to go to fairs and to see the smurfs up front before buying and I am really happy for those of you who can.
4. It does become interesting in regards to the recent Schoenwald sockels. Thanks to Tojo's help, pretty much everybody on here got the last three or four sockels so I am sure a lot of us would not consider them rare at all...however, they were only produced in a limited number (500 I think) so do we still consider them rare or do we not because so many of us have at least one of them?
5. I think I'd want to see catalog proof for that smurf
Just as a add-on to which I really hope nobody takes offense. I may come across of taking too harsh a stand when it comes to "ultra-rare" smurfs and as too distrusting..but while I believe the variations exist, I don't think they are common enough that everybody should look for them...That will only increase the wealth of above mentioned sellers.
I also don't consider a collection with many "ultra-rare" smurfs more special than a collection comprised of more common smurfs, as each collection has something unique about it and really represents the character of it's owner