Hey it's Ubastax guy. I sold my magic collection in 2012 for five houses in North St. Louis, and I've flipped over 150 ghetto properties since. In January I was alerted that a local shop was offering full proxy vintage so I've been playing most Sundays this year.
Stax in any form did not survive the restricting of Chalice as a tier 1 deck, but awhile back u/Zias posted 5-0 in mtgo league with an innovative Prison Dredge list. Combining Workshop, Bazaar, and Null Rod again spoke to me, so I've been running variations on this archetype. I finally went 5-0 in league myself last week. https://magic.wizards.com/en/articles/archive/mtgo-standings/competitive-vintage-constructed-league-2019-03-24
4 Golgari Grave-Troll
3 Hollow One
4 Prized Amalgam
4 Stinkweed Imp
4 Cabal Therapy
1 Black Lotus
1 Mana Crypt
1 Chalice of the Void
1 Thorn of Amethyst
4 Null Rod
4 Serum Powder
4 Sphere of Resistance
4 Bazaar of Baghdad
4 Ancient Tomb
4 Mishra's Workshop
1 Strip Mine
2 Dakmor Salvage
1 Riftstone Portal
2 Riftstone Portal
1 Hollow One
4 Dark Depths
4 Leyline of the Void
4 Thespian's Stage
The differences between my list and Zias
Main: -4 Cabal Therapy, -1 Riftstone Portal, -1 Wasteland; +4 Leyline of the Void, +2 Petrified Field.
Side: -4 Leyline of the Void; +4 Leyline of Sanctity.
I went 10-2 in games and my opponents discarded to Therapy in only two games, one of which I lost and the other I would have won anyway. Also given that Wasteland is the deck's primary weakness both pre and post board, I'm inclined to endorse Zias's maindeck, despite my good showing with this experiment. Sideboard, Tendrils is out of favor for Paradox wincon, and Hurkyl's is not a game breaker for this deck, so I'm still short selling white leyline, though Oath worries me. Instead I have had success holding off creature decks with Vengeful Pharaoh, or I see Spinning Darkness is back in pitch-dredge boards. Pithing Needle could also be worth slots vs Wasteland, as seen in the dedicated Dark Stage decks.
The deck plays along Dredge strategic lines, not Workshop. Its still a must-mulligan to Bazaar (at least game 1), and whatever disruption you can land is bonus. Cutting Moxen is the counter-intuitive breakthrough. It plays 10 cards that produce 2+ mana on their own, and all the disruption besides Trinisphere costs 2, so running Moxen would needlessly increase Null Rod parity. This was unthinkable in the Goblin Welder days of Stax, requiring cheap weldables and casting 4-drops. But Prison Dredge isn't trying for a hardlock, just slow the enemy enough that recurring free creatures carry the game. Its cutting the dredge package down to the minimum and foregoing free counterspells for the bargain soft lock pieces. Prison Dredge doesn't care at all about counter magic or creature removal or artifact hate. It only expects to drop 1 or 2 artifacts at most and can win without casting any. Enemy tempo and cards spent countering/removing your artifacts are not being spent winning the game, so just as good.
General opening hand plays.
Typical: Have Bazaar, Don't have both Tomb/Shop+Sphere/Rod in opening hand.
T1 Bazaar, discard dredge stuff, maybe cast Hollow One.
T2 Bazaar upkeep, play 2+c land, return avg 5 power, maybe cast Sphere/Rod.
T3 dredge a lot, avg 12 power on board.
T4 maybe attack lethal, or dredge most the deck w 15+ power on board.
Strong: Bazaar + Tomb/Shop + Sphere/Rod
T2 Bazaar, discard dredge stuff, play another Rod/Sphere, maybe Hollow One.
T3 Bazaar upkeep, dredge, maybe return a creature.
T4 dredge a lot, return many creatures.
T5 Attack lethal.
Monster: Bazaar + Crypt/Lotus + Sphere/Rod
Plays like Typical, accelerated 1 turn. Can also draw into either Crypt/Lotus or Sphere Rod off first Bazaar activation.
The transformation into Dark Stage is clutch, by continuing to shrug off counter magic while ignoring yard and artifact hate. I easily won one memorable game against T1 Leyline of the Void + Black Lotus->Energy Flux.
Overall this deck has the main dredge upside of Serum Powder into the one card combo cranking out a fast, uncounterable, recurring ground game. It improves on other dredge builds by giving up the creature density and Dread Return big finish for more powerful disruption, plus the mana for alertnate uncounterable sb win, making it not dependent on either the graveyard or artifacts. I'm a fan, London mulligan should make this a tier 1 contender.