Hi,
I had a bit of free time on my hands and also I missed some x64 debugger with command-line (windbg is nice but only if debugging code with symbols) so I started writing my own x64 user-land debugger.
Some screenshots:
http://pespin.com/bugdbg_sc.html
Download (no installation needed):
http://www.pespin.com/bugdbg.rar
Be aware its pre-alpha version so it's not meant for serious work. Definitely more work is needed but I think basic debugging functionality is finished.