I am glad you are as reasonable or more so than I was about the shortcomings and strengths of the Tera Player. I am glad you are enjoying yours and let it be a great example of how you should not see a product and cast it aside from your thoughts but to investigate why these things that first tore you away from the device or item were done, and you may find that your very reasons for not thinking about it in the first place are the exact things you come to love about it.
I have been to Israel and understand how a full sized headphone in Israel is not happening till we get A/C in headphones. Hmm....that actually would be interesting....
Anyways, while I haven't heard them, I believe if we attempt to impedance match the Tera and an IEM that heir audio makes some 150 ohm impedance IEMs but not sure if they are in your price range. You will likely need to read over the previous Tera Player threads to see what people have paired with it and then post here with your findings to get some newer feedback on the list of candidates. I find Head-fi is a great community resource when it comes to getting answers as long as you help get the ball rolling.
Let me start you off. The ASG-1 from Aurisonics while it does not experience bass roll off probably is not an ideal candidate because its at the top end of your range in price and is not a perfect pairing at least from my experience. It is good for a lot of genres but its tuning would not allow you to get the most out of the Tera Player.
I know this pairing hasn't been talked about much, but I figured I could at least provide input with what I know, and hope this encourages you to do your research so not only do you make a decision about the Tera Player but are confident in your decision as the right one.