Just to mention, the Magni 2 Uber has preamp outs if you want an easy way to hook up powered speakers. Still won't match the rest of your stuff, but at $150 it sounds like that would still be in your budget.
With both it and the original Magni as well, and it sounded surprisingly reasonable (with the usual disclaimer that my listening level may very well be half of what yours is, and it was at a meet, etc.)
I only needed/wanted one closed can and decided to keep my Shures instead. I was actually planning on keeping the DT 150, but when I listened to both side-by-side I personally preferred the Shure's treble over the DT 150's bass.