The CanalWorks CW-L05QD deserves a shout-out.
I have the UERM, and it's stellar --- probably UE's best custom product. It has a small bit of high lift, slightly flatter (dimensionally, not talking about FR) vocals, and very minor LF roll-off, but it truly works very well. For me, it needs a tight fit to sound its best; most people have only heard the demo version, and while the demo is good, it's spikier in the treble than the custom version.
The Etymotic ER4B is still the best IEM that I've ever heard with binaural recordings. But I can't listen to it for more than 15 min. straight.
I've heard positive things about the NT6, but have not tried it myself.
The JH13FP has truly great imaging that rivals that of the ER4B, but has too much bass to be considered neutral and has an annoying 6-7k spike. The lower treble issue might improve with a fully custom fitment, but I've only heard the demo version (tried to get the deepest, best fit possible, though).
Personally, I think the EX1000 is still very revealing and clear as a dynamic driver IEM. It's not the paragon of neutrality, however.