The way you say you want them to be less bulky tells me that you might be looking for an on-ear pair of headphones..
I understand that this is the over-ear thread, but, some good on-ear headphones you may want to take a look at are:
If being too bright sounding is your main concern about the KRK KNS8400, then, you can easily use some sort of equalizer to tone it down. If you use an iPod Touch/iPhone for music listening, then get the app EQu. It is far superior to anything that the Apple preset EQs can do.
If you have some other music player, it most likely has a built-in equalizer, so you can use that.
The bulky issue isn't too much of a problem. I just don't want to look like an alien or something while I'm working in Starbucks lol. (Ultimately though, I don't really care if the sound quality is that amazing.)
But in terms of the highs do you find the KRKs to be overbearing? I would just be worried that after listening to one thing for a while, it would start to hurt my ears like most in-ear buds do. I don't mind using an EQ, but I switch things up a lot. So if changing between genres a lot this could get tedious.
Another thing I forgot to mention was sound leakage. How do the KRKs do with sounds leakage? Do they isolate sound while you are listening to music? And also, do they leak when the volume is at a comfortable to loud volume?
(I want to make sure that I can use them in a crowded Starbucks without hearing all of the background noise, and also be able to use them in the library without pissing off the people around me.)