[Hente]

U2311H?
Not the cheapest, but a nice quality monitor.
I've had no issues with either my 23" or my new U2711.
The build quality on both is one of the best things about them in my opinion, stands are very nice.

Would recommend them to anyone.

Should have noted that this or the U2312HM were actually what I was looking at haha, was just wondering if there were any alternatives.

 

[mikeaj]

Some other Dell monitors like P series (e.g. P2212H) should also have portrait mode adjustment.  Those P series use TN panels—so in many situations really not a good idea for portrait mode unless you're down with the left/right sides looking different—and are cheaper than the Ultrasharps.
 
It's not out of the box like you wanted, but the Asus VS229H-P and VS239H-P are also eIPS monitors like the lower-end Ultrasharp range; the stands they come with only do tilt, but they have VESA mounting holes.  These have pretty good contrast, low latency, pixel overdrive controls, so not bad.  At those prices, you could get one and a cheap VESA mount that can do portrait mode for under the typical price of U2212HM and U2312HM.  Monoprice has a VESA mount for around $20 that can orient screens in portrait.