That also doesn't give you a cash pile of $20k at the end of it, after you pay your current rent, pay taxes (higher as a contractor), buy food, etc. I'd estimate the cash pile to be maybe $10k? So his income from that one month was probably more like $30-$40k.
If you are outside of the US for more than 330 days in a 12 month period then you qualify for the foreign earned income exclusion: http://www.irs.gov/businesses/small/international/article/0,.... It does not matter if you are earning money from a US company during that time. I actually did this one year by performing remote work for a US company while traveling around South America.
So, with a little planning, you can dodge at least the income tax portion.
Depends where you live, in the UK I pay a flat 20% (after income and expenses). My monthly costs in London add up to about $2k. So that leaves me about $15k. Not quite as much as the OP but give me a couple more years of experience and I'll be able to put my rates up.
