So, I can't find the time to make the post with the mews I wanted to make (my priority was getting the info, not getting anything new unfortunately), so I'm uploading this save with the info for now, as I've been requested it and there's no reason to keep it (I was waiting until I made the big post, but it's been over a month and still not the time for it).
The save attached to this post contains a Mew owned by Cirellio, who I found over at nintendoage forums. He worked at Toys R Us at Peoria (US) during Christmas holiday season in 1999 and was in charge of Mew distribution for that Toys R US. Unlike other distributions made with Mew machine, this one was made via direct trade with a gameboy such as this one:
He also traded one to his own game, and fortunately enough, he was able to dump the savegame after all this years. What's more interesting about this distribution is the question "were those direct trade Mews also clones with the same DV values as the Mew machines?". The answer is yes, even before the Mew machines were used DVs were already fixed. The only Mew that might have scaped this would be the NINTEN Mew distributed via Nintendo Power, the very first USA distribution. I've read a very old post form an user claiming that these direct trade Mews were all 1:1 clones (all the Mews in the cartridge were exactly the same one, even ID#). This user posted that Mew's OT and ID#, but the ID is different from Cirelli's Mew, so either they were not all clones or each Toys R Us got a different ID#, or maybe each box of Mews had different ID#. I guess the probablity of finding someone with two of those cartridge distribution Mews from the same event for confirmation is nearly null.
Mew OT: YOSHIBA ID: 47310 DVs: 5(hp)/10(atk)/1(def)/5(spe)/12(spd)
Contributor: Cirellio
A great thanks to Cirellio for his contribution to Gen 1 event preservation! DOWNLOAD: https://projectpokemon.org/forums/applications/core/interface/file/attachment.php?id=24562
ps: remember you can use pkhex to revert the Mew to a "distribution state" at level 5, no stat experience and pound as it's only move.
ps2: Yes, it's a Pokémon Yellow savegame and it wasn't out when the distribution took place. Cirellio traded the Mew over to that cartridge from his blue prior to dumping the save.
I'm in the same situation, I contacted an user who had one Japanesse Mew, but he told me that he transfered to GSC and of course battery died out. I'm waiting for respones if that refered to his english games or he also had gen 2 japanesse games and the Mew vanished. I would like to find at least 1 Jap mew.
But you can see here a low quality image of a Mew distributed at Spaceworld 1999. If only we knew if those Mews also had fixed DVs... if that was the case for Spaceworld 1999 Mew, we could at least have one legit pre-VC japanesse Mew (the one from the image).
https://web.archive.org/web/20000901092347/http://www.eagb.net/gameboy/special_space_world99_03.htm