I'd seriously consider looking at the cosmic ears thread. They had a supplier issue, but all reports suggest that their $500 triple driver hybrids are pretty great, with a fun signature rivaling many high priced universals, and they can be made with a lot or a little bass. They also have twin driver BA (two drivers one BA unit) and a dual driver BA (two drivers, in two separate housings), and a quad driver BA, all very reasonably priced. And, regardless of SQ, they are very well made customs, so isolation is supposed to be phenomenal, on par with any top of the line custom. They have single BA models and dynamic models which are both only ~$100
They are burried in the thread, but there are a number of reviews peppered throughout: http://www.head-fi.org/t/626714/cosmic-ears-new-ciem-company-with-crazy-low-prices-including-hybrid-designs
I thought their triple driver hybrid was only around $300 not $500. Their 4BA model will be $400.