Are double denials possible in Finnish?

[PäähäniSattuu]

As in, in English 'I don't want to never do that', meaning that one wants to do it at at least some point. Which could just as well be phrased as 'I want to do that at some point', but 'I don't want nothing' , is not the same as 'I don't want anything'. Can you even say something like 'Mä en halua ei mitään'?.

Also 'I want nothing' is 'mä halua en mitään' right?

[jahasjahas]

As in, in English 'I don't want to never do that'

How about "En halua olla tekemättä tuota."? (Though that's more like "I don't want to not do that." or "I don't want to miss doing that.", no strict "never" there.)

'Mä en halua ei mitään'?

I can only see that working in a scenario like

- Mitä toit mulle lahjaksi?
- En mitään.
- Mä en halua "ei mitään"! Mä haluan ponin!

So not really what you were thinking of.

Also 'I want nothing' is 'mä halua en mitään' right?

"Mä en halua mitään" would be the expected word order. "Mä halua en mitään" could be used in a poem or a song.

[Pursuivant]

Puhekieli maybe...

Mä olen ilman mitään?
(I am without anything)

[Valinnan vapaus]

Ei kyllä ei millään tuu mitään mieleen... ei sitten ei millään. <-- colloquial or something

I think the answer to you question is no, it's an idiomatically English (and even so American/colloquial) phenomenon to start with.

[AldenG]

I've heard Finns in Finland say "I cain't get no satisfaction."

I guess that doesn't count on two counts. Not really Finnish and not the kind of double negative you wanted.

[PäähäniSattuu]

Ei kyllä ei millään tuu mitään mieleen... ei sitten ei millään. <-- colloquial or something

I think the answer to you question is no, it's an idiomatically English (and even so American/colloquial) phenomenon to start with.

Well, it can theoretically happen in any language where negation is just a random particle which be done to almost anything. I assumed that in Finnish since the negative particle is the finitie verb of the sentence of some sorts I wondered how double negatives, if at all, are possible in Finnish and apparently they aren't.