Seems interesting, would probably never try to do it. But I think there's a few things to note with this challenge.
1. World gen. Mod the raws for a dwarf-only micro world, end it year 50ish. You'll need migrants to get to 10k supposing you want to do it legit and not just spawn migrants in. Otherwise end at year 5. 1x1 embark will be fine, but you can do a 2x2 or 3x3 with little impact to your FPS compared to what we're about to do, so I wouldn't bother with 1x1.
2. Develop fort with absolute minimal pathfinding from one, singular tavern. You will have no labor shortage and all jobs will be done except sustaining your population by the time you're at like 10k. Everybody can *probably* be naked without going insane, since everybody will be spoon fed tavern happy spam. Main paths should be tavern, dining, food stockpile, and beds (probably do a "dorm" for everybody with artifact cheese), so all of those should be basically adjacent. No hallways between those main things. Minimal armor for everybody is optional, but clothes should be destroyed. Siege deleter (bridges) is advisable, and stockpiles should be absolutely minimized since labor speed isn't nearly as important as keeping as few dwarves working as possible. Temple and library are inadvisable since a dwarf can make do with just the tavern and we don't want them walking anywhere.
3. Once your fort is designed, open the floodgates. Spawn em all in or semi-idle your game for a bit. When your fort starts filling up, make sure everybody who isn't strictly necessary is sitting in the tavern idling, where they won't be doing much pathing except for base needs of sleep eat drink, most of which should be happening very close to the tavern.
4. Other things to note: seal caverns (you need one layer for dwarves to exist), embark somewhere barren like a flat mountain, DFhack 'hermit enable' to disable caravan, migrants, and visitors (after you reach 10k, of course), and temperature and weather off of course. None of these will be that important since they don't scale with your population, but they can help a little bit.
1x1 necro/intdead prisons are also an option, but I feel like it's slightly less in the spirit of the challenge.