This is utter and complete hogwash.
A solid business plan and decent personal credit history will get you into an SBA loan with no trouble at all. Yes, some banks won't do SBA for < 2 years in operation but many will. Start with banks that have a local presence in your area. Also, US Bank is one of the big ones that is quite bullish on startups. SBA requires 15% owner equity for startups but that means you're good for $1M with only $150K in.
Of course, don't expect to be greeted with all handshakes and smiles with a 3 page vision statement. You need to know accounting inside and out, because the bankers sure will. They can sniff out unrealistic cash flow expectations in seconds and show you the door. My business plan was two years in the making and over 50 pages long. My full SBA package was well over 100 pages.
I also disagree with the classical "double it" budget mantra. That simply means the business plan was unrealistic from the start. Yes, set aside some budget for contingencies, but don't guess numbers. If you have to guess, go ask someone. I *do* agree with the double (or triple) the time needed. Like it or not, you'll be dealing with over-worked, under-paid government officials that have massive backlogs, from permitting to inspections, to licenses.
My best advice is "Don't quit your day job" until hooch is going out the door.