I feel your pain, Bienville. I’ve got a couple specific songs I’ve been trying to find for literally decades.
Anyway, your video reminded me of a few things. Barring tango (which you said is wrong, but there are different type of tango music and similar S. American styles), the first was Brahms’ Hungarian Dance #5. Which is actually pretty close to a mazurka, now that I think of it. And would have been inspired by the music of folk bands that more than likely would have included an accordion.
But, there are many similarities between different European countries’ folk music and their offshoots. Compare German to Mexican (if you get bored with your wild goose chase, look up the history of norteno music, it’s fun :D) and then over to Cajun Zydeco which sounds like Scottish folk mixed with only a dash of French. Classic French blends well into Italian, and then you get to Sicilian music, which is just a short hop into (former) Yugo folk music…some of which sounds just like the German thing I linked.
I mention the French and Italian together, as their traditional music tends to be in 3/4 time, as in waltz. The others I mentioned are more 2/4, 4/4, or 6/8 (which you would think would sound like a waltz, but usually doesn’t)**. What you were humming in your video was definitely not 3/4, and probably not 6/8, either. Which pretty much rules out the bal-musette, as you noted, and a lot of Irish and Italian music. Hope that makes sense. Oh, and any of those time signatures can have a strong leading beat like your rhythm.
Hem. Where was I? Oh, yeah. Bottom line is, your rhythm seems definitely folk-ish to me, but it could be from almost any Western derivation. To make things more complicated, American pop music in the early to mid 20th century, just like the Romantic counterparts in the late 19th century, was often heavily drawn from the music brought over by the different waves of immigration.
Anyway, I wish I could help more, but I’ve really got to go to bed. I hope I’ve given you some good food for thought. You certainly gave me an amusing hour or so listening to different types of music! 
Oh, and you might try Musipedia. They’ve got several nifty ways of identifying music, from typing in notes, to playing rhythms, to humming into a mic. I know you aren’t looking for a specific song, but its wrong guesses might get you most of the way there. In fact, that’s how I came up with the title of Brahms piece, because I know the song well, but couldn’t think of the title for the life of me…kept thinking it was one of the other folk-inspired Romantic numbers. So I punched in two bars worth, probably in the wrong key, no less, and got it in one.
**(The further east you move in Europe, the crazier the time signatures–not to mention key or mode, or seeming lack thereof–can get. Here’s a little primer on regular and odd time signatures I just found, re:Southern and Eastern folk music, with example songs. My musical knowledge is very piecemeal, unfortunately)
