I was wondering what the largest possible system size is currently and also what size people have seen in game.

how about this?

Holy cow... Where did you find those things?!?

*drool*

Still haven't found 80

I dare say sir p. won that game (he "found" it, actually he wrote a batch program and had to make about 400 cycles until that world showed up ).

so every 1:400 games, you get one world with >100 bn. pop. but 80+ will be much more likely to get than that ratio I'm sure.