Remove x number of lines from beginning of file

[Nicholas Leippe]

You could configure a loopback device on the file with an offset, then access 
the loopback device's block device as a file. If you need to append to the 
file, then you will need to pad it first and know at what offset to begin 
writing--or just append to the original file, but it won't be accessible to 
the lo device (and you shouldn't write to the portion of the original file 
mapped by the lo device).

Depending on your end goal this may or may not help.