In no particular order I would recommend B&W speakers from the 800 series and also the Dynaudio Contour and Confidence lines (though some find the Bryston-Dynaudio a bit on the cold side).
Dali Helicon and Euphonia lines might also be a good match. I have audition at home the BP25 pre and the 4BSST amp for a week. I used them to drive a pair of Dali Helicon speakers complemented with a REL Stentor 3. The combination was quite good.
Finally, the BP25-4BSST combo sounded terrific when driving the MBL 121 speakers.
Dali Helicon and Euphonia lines might also be a good match. I have audition at home the BP25 pre and the 4BSST amp for a week. I used them to drive a pair of Dali Helicon speakers complemented with a REL Stentor 3. The combination was quite good.
Finally, the BP25-4BSST combo sounded terrific when driving the MBL 121 speakers.