Disclaimer: Take this with a grain of salt since we don't know the exact mechanics of Alchemist's Mark yet.

https://pastebin.com/5VAFrHyu

Other people have realized this already, but Alchemist's Mark should work extremely well with very large single instances of poison/ignite.

I've mocked up an Occultist version and a Trickster version (with a jewel to simulate the new ascendancies), both of which use Low Tolerance (and the identical Poison Mastery) plus Hound's Mark curse clusters to ramp Alchemist's Mark's damage into the sky.

I've made a few assumptions here:

1. That Alchemist's Mark does truly base its damage on the ailment's DPS, not its total damage (I've seen some people say the latter)
2. That it functions as a more multiplier for these builds (aka, while it isn't affected by damage mods, it SHOULD just copy the damage of the ailment at whatever curse effect)
3. A 30% increased mark effect enchant will exist for Alchemist's Mark

A few problems I'm not totally sure how to solve:

1. Mana - for Occultist I take Mind Drinker, and Trickster also has the option of taking that + the reduced mana cost mastery, but I opted to drop it because Polymath gives so much mana on kill. Shaper shield w/ efficiency on it for the 3 big auras would be good. Otherwise, this might just be a mana flask build.
2. Physical mitigation - Gravicius mod does a lot of work, but you definitely need more phys taken as ele/chaos, or a source of endurance charges. Endurance per X seconds on chest or an accumulator wand might work
3. Clunk - I personally haven't played a build like this before, but it SHOULD be pretty much identical to ignite hexblast...except no prolif. Pathfinder MIGHT be viable if you want prolif (and you can steal Focal Point), but I haven't tinkered with it. I also don't know the exact feel of Doomsday + Hexblast.

A few other notes:

1. The hinder curse mastery should be interchangeable for the blind curse mastery for mapping, but you'd need another source of hinder for Touch of Cruelty. I also kind of prefer the hinder just because it helps keep more mobile enemies in the Alchemist's Mark poop.
2. Soul Drinker vs One Step Ahead is kind of personal preference for the Trickster version, but the recovery is a little iffy to me so I prefer Soul Drinker.
3. The advertised DPS is likely to be quite a bit lower for Trickster, since Hexblast will eat Despair and your poisons only last ~1 second. Occultist gets around this by having an extra curse for Temp Chains; if you can get a third curse on Trickster then it should work out the same.

This MIGHT be league start viable as Trickster, although I have Ashes of the Stars in the PoB, and without it you have to drop Malevolence. I also only built CI versions without life/hybrid versions to get there, so I probably wouldn't unless you're confident. I definitely wouldn't start the Occultist version because while she has more damage, she's a LOT squishier due to a lack of suppression. I DEFINITELY wouldn't start either version in SSF because of the reliance on clusters. We also don't know how rare the new Doedre's Scorn will be, but it's easily replaceable and I mostly just picked it to juice Alchemist's Mark even further, assuming it scales well with levels.

I'm personally probably going to start Boneshatter since they've lightened up the archnemesis mods a bit, but I'll keep this on the backburner just in case, and I'm definitely gonna try it 2nd or 3rd build.

edit: Sorry for the giant chunk of text, I don't post a lot on reddit and I'm not totally sure how to format better.