I find myself around 3 different company owned T-mobile stores daily. 1 by my apartment, 1 by the subway on the way to work, and another down the block from my job. Combined, each one gives a good representation of what T-mobile is offering in general... Meaning that none of the 3 have the same total inventory, and they all have more to offer then the others. Depends on your phone I would guess. For example, I won't stereotype but the T-mobile by my apartment has a TON of stuff for the Samsung Galaxy line, while the others have either more HTC, LG, and oddly enough a lot of Nokia. Like I didn't even know there were that many Nokia accessories available...
My point is, I've asked every day in a combination of the 3 stores if they have covers or cases yet for the N4. Each store either pulled something out of their ass, or were at least straight with me by saying no, and they don't know when. This is as of today.
What I ended up doing on Wednesday was heading to the AT&T right next door to my job to pick up a LG Optimus G bumper case. Obviously not perfect, but strangely enough very ideal. It actually made me want to get the Google bumper case because it frames the phone well while showing it off. Unfortunately though, it was designed for the Optimus G. It really "squares" off the phone a lot, to the point where it looks like you actually have an OG in there. If you can deal with the bulk till something more ideal comes along, I recommend it.... Here's the rub though. On Friday, I received the thin TPU case that I had ordered from eBay. It's definitely worth the $3 I paid for it, but I'm still holding out for either a 3DO or a bumper case. I'll keep asking, and I'll update this post if/when I find that T-mobile has cases in the stores.