The Dynaudio Audience 72 and 72SE (upgraded with drivers from the Countour 1.8 mkII) are front ported speakers and will fit your budget from the used market.
Alternative to Dynaudio 1.3SE
I currently own a pair of Dynaudio 1.3 SE's. They sound great on most of the material I listen to. My problem is I can only place them about two feet(measuring from the front of the speaker)from the rear wall. On material with moderate to heavy bass I get too much boominess. I have been looking at some front ported speakers such as the Tyler Reference monitors. Would the Tylers be in the same league as the Dynaudio's? Any other suggestions? I can spend around $1500-2000 used or new. Thanks.