Small amount of work, just 1 function call on NT 5,

Just one function call eh? I'll believe it when I see it working.

You might want to take a look in lnw.cpp

Use a CPAN module Win32::HardLink as mentioned in the thread, no need to reinvent the wheel.

Accept it doesn't work:

C:\test>dir /b pete*
File Not Found

C:\test>mklink /h pete.exe \perl64\bin\perl.exe
Hardlink created for pete.exe <<===>> \perl64\bin\perl.exe

C:\test>pete -v
This is perl, v5.10.1 built for MSWin32-x64-multi-thread
[snip]
C:\test>del pete.exe

C:\test>perl -MWin32::Hardlink -E"say link( 'pete.exe', '\\perl64\\bin
+\\perl.exe' )"
CreateHardLink( "\perl64\bin\perl.exe", "pete.exe" ) failed with error
+ 2.
0

C:\test>pete -v
'pete' is not recognized as an internal or external command,
operable program or batch file.
[download]

Win32::Symlink works after a fashion, but looking at the code that underlies it, I wouldn't want to rely upon it.