I'm number 57 out of 295 users as far as shares submitted (1958 shares submitted) and it still shows 0.00000000 BTC
I'm hoping that as more blocks are solved it will show something, but to ease the minds of your workers you should really show "Estimated BTC Earned This Round" so people don't keep staring at 0 BTC for hours and hours
'Estimated balance based on your amount of shares on the current block that we're working on' has been suggested earlier, and might pop up. It's on the projects todo list. You have to understand that there are a lot of things being worked on.
I do not personally like this, since it brings false hopes. And just watching this thread, there's very few who actually understand or have a few clues on how things work. Maybe it'll ease their minds, maybe it'll piss them off seeing the estimation go away without the balance updating.
You are correct in that it takes a while before you'll see your balance update. The pool must first solve a block, then wait for it to actually bring in spendable cash.
This is currently a small pool - which means there's no margins or buffers. I would guess the larger pools have buffers, so that they can have an even more "realtime" instant payout.