O-1 w/o lawyer is not only impossible, it's the way I recommend to everyone who already achieved smth in homeland country.

I received O-1 visa in February 2015 and I did it without lawyer. After I id it, I helped a couple of my friends and they received O-1 as well. Again, without lawyers.

All you need is:
1) learn USCIS docs (law itself and directions on the official site)
2) learn as many examples as possible (in my case I found some "DIY O-1 visa" zip in the internet and bought it – it was smth like $150, and although it didn't contain examples from tech, it helped a lot to get proper understanding)
3) examine all your professional life and recall all possible achievements. It cannot take 1 week or so. It should take at least month – because otherwise there is a chance that you miss something that could improve your application.

I have now a deep belief that lawyers in case of O-1 can be really helpful only to those founders who are too lazy. No lawyer will do the most important work on O-1 application for you: it's you who should recall your achievements (prizes, your articles, articles about your and your project, etc), it's YOU who should ask YOUR connection for reference letters, and so on. In many cases lawyers even can be a reason of failure of application: for example, they can miss something important in writing reference letter for you, or even make some fact errors. Or even worse, they can be reason of delay in delivering RFE response from USCIS to you, what can automatically lead to failed application since you then have no time to prepare a good answer. (All examples I mention here are from the real life...)

So my advice – don't be afraid to DIY, save $3-8k (SF lawyers' prices for O-1), learn the law and examples and DIY! Yes, this process is not really simple but it's definitely doable, and since nobody know your life better than you, nobody can prepare O-1 application better than you.

Of course here I should place disclaimer that I'm now professional lawyer and cannot give professional advice in legal areas:) And don't forget that for O-1 you should have a company that will hire you (actually in terms of law, it's the company who officially files the application for you -- the company is a petitioner in this process) – this may be the most difficult point for those who work for themselves.

A couple of additional comments:

- RFE process ("request for evidence" – when USCIS asks you to provide more information) always occurs, and you should carefully read eveyr USCIS's comment and respond to every comment very clear, this is the key of success.

- Once you file your application, if you're in US on your B1/B2 and don't go outside, you receive "pending" status which means that now you're purpose of stay changed and if it is needed, you are able to stay in the country more than the stamp in your passport indicates – you can stay until USCIS's decision on your application. And when you get RFE answer from USCIS, they give you a couple of months to prepare your response. So technically you can enter on B1/B2 and stay more than 6 months without breaking of any law. I stayed 7 months and it is ok (however, on my next travel to US, I had to wait for additional "clearance" checks in JFK – but it took 15 minutes or so).

- Visa != status. Visa is used only for entrance. You can enter on B1/B2, then get O-1 status and live on it. But once you leave US, you cannot return to the US. Because you need visa (stamp in your passport) which can be made only by US embassies outside the US. So you should go to US embassy in your country and get O1 visa (based on USCIS decision made previously – but be aware that here, once again, additional "clearance" checks can wait you).

Hope it will help somebody.

I wish good luck for those who try to DIY O-1 visa. In case you do it, it's a double-victory!