If you are going to add binary file access, don't forget "seek()" to skip to a specific byte in the file, and "trunc[ate]()" when writing to delete the end of a file.

Also, it would be nice to be able to read/write simple strings when you know the the data is not going to contain hard to handle characters. In this case you will need to be able to specify the number of characters to read.

How about presenting the file as a stream, and just return the characters, something like:
Code:
If OpenBinary(1,"somefile.doc","r")
   "Could not open file for reading!"+@CRLF
Else
   $c=ReadChar(1)
   While @ERROR=0
      "Got character #"+CStr($c)+@CRLF
      $c=ReadChar(1)
   Loop
EndIf


This way it kind of follows the existing command syntax.