Check out audiostream.com, lots of good recommendations but I believe all of them are active/powered, which works out really well to save desktop space when coupled with a DAC/preamp. Note I own Dynaudio BM5 Mk III's which are one model up from the professional version of Dynaudio X14A, their favorite monitor but I've only used them in-room.
Recommend use of IsoAcoustics stands to provide proper height/tilt, help isolate vibrations, and reduce bass reinforcement/echo from the near proximity of the desktop.
Being so near-field you should avoid deep bass response, F3 of 40 Hz is pushing it, 50 Hz is plenty, 60 Hz is enough.
Physical size is a personal decision. Years ago I freaked out the first time I saw a 21 inch monitor on a desktop, now it's common place. So I suppose you could get used to large monitors. But professionals consider 3-ways as mid-field monitors and many prefer the 5 inch woofer version compared to the 8 inch version of the same monitor.
If you are interested in active monitors check out soundonsound.com.