here's a few high end iem:
aurisonics asg-2 (i've ordered and waiting for it to come XD)
fitear tg 334
Are you specifically looking for IEM's and not custom IEM's?
I agree that with that budget, I would go customs all the way. But it's near impossible to audition customs too, so that can be a factor.
But if you are listening to them 5 hours a day, I would think customs would be more comfortable too. Mine are, for sure.
The best IEM depends on your preference, but the best IEM I have ever heard is the Tralucent 1plus2, followed by the UM Miracle, K3003 and FI-BA-SS. I didn't like the metal FAD ones because they just don't fit for me. Really want to hear the TG334 and IE800 and see if any of those best the 1plus2.