Basically, I don't think the nemesis gown is tagged at all. In trying to find them I searched "gown", "dress", "nemesis", "blue, dress", but they didn't show up. I ended up trawling through every page of the clothing stores.

-trying really hard to point out an issue without feeling complainy-

You're right they're not properly tagged. (But that's something for the AA's to take care of :P )
In the mean time though if you're still looking for them they're currently under the "wishie was here" tag and can be found in Emporio Palazzo shop (pages 11 and 12)

Thanks! I did find it eventually, but it took a lot longer than I would have liked.

Haha, yeah Wishie "helped" with tagging a lot of the commons for that event. Tagging really is a total nightmare, there are endless items that have temporary tags, or still have the stupid auto tags that Inso added back when he initially introduced tagging.

One day they will all be fixed

Are the Bellatrix gowns in a similar state? I don't remember seeing those in my searches either.

The Bellatrix dresses are tagged.
http://www.menewsha.com/marketplace/....php#bellatrix

I am clearly as blind as a bat. Thanks!