I did this as Bismark / German people (please note Emperor difficulty, Beyond the Sword version, latest patches). It wasn't easy, though i reached 1 BILLION in 1995 or so. I'm not sure if its possible without corporations (which are only in BTS AFAIK, but probably yes), aka Sushi and Co. I didn't finished the game yet, but i will, and then i'll send you screen. I'm trying currently reach maximum population and global control for fun :] (i won historical).
Currently im on 40 with Danzig, but London, Inverness, and Tours for example aren't fully developed yet. Also the main reason why i didn't finished yet was nuclear war in '95 or so

Which as you know means global warning, and that's absolutely no good for this kind of stuff.
BTW: Suggestion to other challenge: did you ever build / get all possible wonders (which means: possible wonders from 600: Notre dame, Learning Tower, Spiral Minaret, University of Sankore, Wat Preah Pisnulok, and all the other) on emperor difficulty? (From later start.) It's pretty tough i think, i did it after literally few years of playing

) In my game i've build everything except Notre Dam (build before i started in 840 in Constantinople), which i conquered from Byzantine empire ASAP.
Now it's the other part, i actually cheated a bit (or changed the rules), because i played it as custom scenario with technology brokering, and some stability logging (which can cause some random bugs, but _hopefully_ doesn't - and i did it because i needed to understand the stability exactly - like running representation + bureaucracy with 20+ cities and similar extreme stuff without loosing stability). And i used save / load plus minus normally. It shouldn't affect the game rules a lot (you know the tech. brokering was enabled in prev. versions.)... anyway i'll try it later with vanilla version / settings later, but unfortunately i don't have any time for this in near future.
So good luck and have fun. (Screens later, i currently doesn't have access to them.)