A new unnoficial build based on original FCE Ultra, FCEUltra Win32 mappers modified (check it out!), and some other tweaks by nitsuja/blip, Ike and others has been released. Actually this is the second release, but looks cool enough. Here's a summary of the many changes of this Luke's version
Luke's FCEU modification
More info here:Changes 98.16
Added mappers/boards from the memory-mapper FCEU project.
Added a rewind feature. You must enable it manually every time because it's a little experimental. All it does is save a state every few seconds to "rewindX.fcs" where X=0,1,2,3, which you can load by pressing the rewind hotkey (default "R", can be configured). (Note: If you're running more than one instance of FCEU, only use in one FCEU at a time or you will get unpredictable results.)
Added a support for a hotkey to view the save slot you're on. (No default key--pick it yourself in the configuration)
New input display. Press the input display button to cycle between 0, 1, 2, and 4 controllers displayed.
The "Run in Background" option now works correctly. Added an option to accept input while running in the background, which should be useful for making multi-game movies.
Compiled some parts with higher optimization settings, so you might get a small emulation speed boost.
Fixed a subtle bug (introduced by the shared memory code) that made FCEU crash in some cases eg. Bio Hazard (unl).
Added absolute value "abs" and "setcounter" to BasicBot. Also added "mem" which gives access to all memory locations 0-65535 (unlike "ram" which only could do 0-2047).
Memory watch can now access all memory locations 0-FFFE.
Memory watch is now throttle-friendly. It won't slow you down when you increase the throttle.
A little more space for labels in the memory watch window.
Memory watch and BasicBot remember the last directory you used, even after closing FCEU.
Fixed the autofire not working 1st frame after loading a state while recording a movie.
Attempted to fix the read-only toggle glitch adelikat mentioned. Maybe it will work now?
More throttling speeds for people with crazy fast computers.
A few glitches no one will ever notice (unless you read the source code) have been fixed.
You can now run multiple instances of FCEU. (Previously the shared memory would screw them up, now only one copy of FCEU will use shared memory. Hopefully
BasicBot is now implemented.
Many enhancements to the speed of bot emulation. I think I killed the slowing bug, let me know if your FCEU is still running slow. On my computer this runs the same as the original FCEU.
Autofire offset will stay in sync when loading a save state while recording. Known bug: the 1st frame after the load, it could fail to fire when it should have. But it's still better than having to readjust the offset all the time.
Added some commands to the NES menu so you don't have to hotkey them.
Luke's FCEU modification