B15, odd clunk noise

[Jim Wright]

Hey all.  Got an issue that just started in my '06 Spec V.  Kinda hard to describe, kind of a single 'clunk' noise at odd times.  I might hear it backing out of the driveway, going slow down the street, but can't hear it when going at highway speed.  Tried to listen with the windows down, but still couldn't pinpoint it.  Definitely coming from the front, can't decide which side, seems very close to the firewall.  Seems to happen when speed changes (something shifting?), but not really tied to the transmission shifting, or bumps.

I've checked the front struts and what suspension I could access, nothing seemed out of place.  Had tires and front brakes put on at the beginning of the month, shop did an inspection and didn't find anything (I didn't ask them to investigate), dealer did an oil change and a slightly better inspection last week (again didn't ask them to investigate) and nothing was mentioned except a leaking rear strut and a cracked serpentine belt (what fun those are to replace!).

Changed the rear strut, still hearing the noise.  Motor mounts look good, car has under 50k miles.  Thoughts from the gallery?