YC has now funded enough companies that if it has the data (likely in a bunch of spreadsheets) to do a more accurate version of this. Expenses aren't really flat, growth isn't purely exponential and today's estimates aren't reality. A simple model that fixes those three things, should improve accuracy though it would still be subject to enormous volatility which could also estimated based on the same history. This also ignores optionality and probability of a failed raise which would further shift the answer.
This is more of a tool for thinking about growth rate, startup capital and expenses in general than a model for calculating an estimate of any kind. For that, you need to make your own for your business.
"A good growth rate during YC is 5-7% a week. If you can hit 10% a week you're doing exceptionally well. If you can only manage 1%, it's a sign you haven't yet figured out what you're doing." - http://www.paulgraham.com/growth.html
This little app can help put those into perspective.
You're assuming that YC has this information from all the startups they fund. I doubt this for two reasons: YC is probably too busy to spend time collecting spreadsheets from everybody; and from what I've seen, most startups aren't careful enough about their accounting to have the data in the first place.
I doubt there's a formal collection but I'd be equally surprised if they don't have early stage projections from many of the companies. As silly as they can be, they're often part of pitches.
From my limited personal experience, every startup I've chatted about this with has some sort of forecast though the degree of seriousness with which is was constructed and is used varies.
I'm now working at my 3rd YC startup. Sometimes we show our Leftronic graphs to investors, but other than I have never seen someone send hard data to YC. YC is very hands off. You do a weekly dinner the first few weeks, then you do a demo day, and then after that maybe sometimes you get an email once every few months asking how you're doing. Maybe you go visit when you have a question or are bored. That's about it. Other than that you just write code and talk to users.
