Near-field listening calls for a very smooth on-axis response without any harshness or midrange colorations. Ideall, the radiation pattern would be symmetrical and the drivers would blend well at very close range (not always the case, especially with first order crossovers). If the speakers will be placed near a wall, then preferably they'd be voiced to have extended, smooth bass with the nearby boundary reinforcement. If the speakers will be placed out in the room a ways, then they should have rather full bass response so they won't sound thin.
Speakers with concentric mid/tweet units - such as the KEF Uni-Q series, small Tannoy dual concentrics, or Gradients - are inherently well suited to near-field listening (assuming they are voiced correctly - I haven't heard the KEF and Tannoy offerings). I'm most familiar with the Gradients, 'cause that's what I sell. The Prelude is a little above the specified price range, but occasionally a pair shows up used. The custom Seas concentric midwoof/tweet unit they use is the same unit as used in the highly respected Revolution. The midrange is very smooth, and overall tonal balance is neutral when they are fairly close to a wall, but the bass is a little thin if they are placed well out in the room. They use a sealed cabinet, for good transient reponse and a slow roll-off.
I'd be glad to answer questions and/or arrange for an in-home audition.
Best of luck on your quest, Richards!