Awesome
Shellcode Tester
A shellcode testing utility that allows payloads to be disassembled in 32/64bit NASM syntax using BeaEngine.
Tool also has the ability to run 32/64bit payloads against calc.exe for simulated testing.
The application is targeted towards a 32bit build and allows shellcode to be tested against itself, but could easily be used for 64bit if modified.