Why do they need to grow so fast? You didn't ask this question. Most of the answers operate under the assumption that they expect to add 35 individuals and have everything work smoothly. What if the answer to the question is, "We want to have a large staff to attract investors."? I heard a story where programmers used two and three computers because the company used Number of Desktop Installations to indicate the size of the company. You can't make this stuff up.
Things to address/mention if they are still convinced they want to do it:
Leader or "Yes Man" - They want to see how you push-back on management requests. Can you confidently show them the error of their ways without offending them? Offer valid alternatives.
Existing Staff Retention - Make sure your existing staff is going to be comfortable working with a larger team. You may have people who chose this company because of the small size.
Nobody's Perfect - be prepared to hire more than 35 new people. It could get closer to 40 with loses and those that aren't going to cut it. Yes, you have hired and will continue to hire people that don't fit, but show you can identify poor choices early and make corrections.
Referrals - Everyone you hire needs to bring in two other people. It works for multi-level marketing. Wouldn't it be great if you could hire 5 people, who bring in 10 people, who bring in 20? Boom - 35 more people. Now, back to reality.
Better Jobs - Will the company be able to offer: flex-time, remote workers, competitive salaries, meaningful work, and all that other fun stuff you'll learn from existing and future candidates?
"Poaching" - there's only so much talent to go around and many qualified candidates will already have a job. This company is going to develop a reputation of going after other people's employees; they may not want that stigma.
Feeder System - Having a relationship with local universities with CS programs can help in the short-term if you can develop an internship program and some part-time positions. A 6 month time-frame makes it difficult to only go after graduates.
Cash - This is not a bootstrap situation. This demand can be met, but the costs need to be realistic. You want a lot of resources in a short amount of time means you'll spend a lot of money. Much of the money will be wasted. You may be hiring temp staff to go through all the resumes, schedule interviews and manage the line of candidates going out the door. You're company is going to look like the hottest day-time geek club on the planet.
Current Projects on Hold - The current programmers may be spending all of their time building a website to manage hiring. The rest of their time is going to involve interviewing and evaluating new candidates.
We look at this hypothetical task and immediately identify how obsurd and impractical it is, but we should always focus more on what the customer's definition of "working" is. Look past that. Maybe money is no object.