You wrote that a read-only app would work. Then I highly recommend you to try **[Lister][1]**.

It's a part of [Total Commander][2] but has standalone version. It's a small app that can view really huge files very fast. 
Features included:

 - Print file
 - Find in file (supports RegEx search)
 - Different view modes and charsets (you can see in screenshot)
 - Supports plugins for different filetypes and new features

![Lister window][3]

All that in ~500 kb file. For screenshot I opened VirtualBox hdd image which size is 10 Gb. Navigating in file is instant. Searching for string took less than 30 seconds untill first hit in the middle of file (I suppose that it depends on your HDD speed). And RAM consumption is 5.7 Mb for this file.

  [1]: http://www.ghisler.com/lister/
  [2]: http://www.ghisler.com/
  [3]: https://i.sstatic.net/9e1gI.png