DDMs cannot isolate squat and getting a good fit is well, a game of luck for most (I was too lucky). Otherwise, they are a better fit in terms of bass punch, dynamics, sound stage.
In terms of pure SQ alone, I'd say FX700 is the best fit. It has got a great sound stage, excellent bass punch, but offers minimal isolation.
FXT90 is very different from FX700. It's much more smoother in presentation with more forward mids, lesser emphasis at either end, but thankfully it offers slightly better isolation. It also has a good sound stage with imaging. It's not exactly a fit for your V-shaped requirement, but none the less a choice to consider. It takes a bit of time to get used to, but well worth it. But, I won't go as far to say that this is the best I've heard - EX1000 and FX700 are the best dynamics to my ears. So, take those head-fi opinions with a pinch of salt.
From what I've read, IE8 does not offer great isolation. IE8's treble may be more laid-back too! I can only speculate that much about something I've not heard. IE80 is out and has more forward mids and lesser sound stage size. IE10 should be out next year.
TF10 fits your requirements more than anything. V-shaped, wider sound stage, great depth, very good imaging capability, detailed yet fun, good bass punch and sparkling treble. Technically, I'd say it would score less than GR07, but fun wise, much better!
I think Sony XBA-3SL would be in the same mold as TF10. But again that seems a bit huge as well. Not many impressions out there, but you can buy directly from Japan using Tenso for a little over your budget -
Rakuten: Sony XBA-3SL- Shopping Japanese products from Japan
GR07 is a jack of all trades. It has an excellent bass presentation, more balanced, very good weight and texture to the sound, extremely comfortable, good set of accessories. Yet, it's undoing for me was it's sibilance and I have many recordings that have vocal sibilance present in them. If you can EQ it very well, it would become flat in FR. It misses the last bit of extension in treble though!
Edit: After reading thenvk's post above, if you need something middle of the ground - consider FXT90 and GR07 (both over the ear). Technically, I'd say GR07 is slightly better, while FXT90 is more on the colored side. Don't exactly remember, but GR07 would stick out a little less than FXT90.