Not really same issue, but just to report a similar case using i7 1.8Ghz.
I'm using a 13'' MBA with i7 1.8 (2011) and Thundebolt display, docked and lid closed most of the time.
Sometimes I experienced similar problems and that's really annoying, I was tempted to return both to store...
BUT the fan is not running all the time in my case, most of the time it spins about 2000rpm and I can't even heard it.
As soon as I open a streaming video, I mean any kind of it (flash, html5, skype with webcam, etc..), cpu go from 60C to 97C and fan spins at 6000rpm, really noisy.
The strange thing is if I open an HD 1080p video, even from a network share, fan and cpu still seat without even noticing it, no noise at all (...quite same job, play a video and network activity, heavier to decode than a crappy 360p flash clip).
I thought it was something flash related, but it happens same thing with skype or by using youtube in html5 mode.
As final test, I tried download one of these video as .flv, playing it with VLC or Quicktime and again, no noise and no heat.
Since I read there's similar problem with MacBook Pro 13'' (not on 15''), and since they share the same cheap CPU integrated video card, I suspect there's something weird happening while streaming video run on these macs.
As a proof of this, if I simply hide the streaming video by switching browser tab or desktop, the fan and heat disappear, even if video is still running (so decoding it's not the problem, I can hear video audio as well even in background).
This *****, my "old" 2008 15'' macbook pro core duo plays well same videos.
I hope a real fix will come out, upgrading last firmware,etc didn't change anything...