Let's say comments make up 10% of my lines, white space makes up 10% of my lines, and a single } makes up another 10% of my lines. That makes 7000 lines. Let's say every line is filled with 80 characters that I have typed (no auto indent). Let's assume there are 5 characters in the average word and I type at 80wpm.
With those paramaters it would take about 23hr to type. Luckily I have an IDE, I comment a lot, and I indent and make a lot of whitespace to separate ideas between lines.
OK, I can see that by the numbers it is possible, if you have planned everything so well that you don't waste any time getting stuck or rewriting. While I do this for much smaller amounts of coder, 10k LOC is so much that I don't think I could possibly plan it out that well, and also keep it in my head. Personally I find that my plans fall apart once I actually start to write out the code and notice many things I forgot, and usually I find the code is much uglier than expected and I try to find better ways.
With those paramaters it would take about 23hr to type. Luckily I have an IDE, I comment a lot, and I indent and make a lot of whitespace to separate ideas between lines.