It is called "styleclock" I think... don't have my laptop around to look for the name... but I think it was styleclock ... and.. it is themable :-) Very easy by the way, since it uses jpegs...
It seams fine but it won't work with me. My layout is something like
[code:1]
---------------------------------------------
Taskbar | Tray | Clock
---------------------------------------------
,-------------------------------------,
| Hiden kicker and launch buttons |
[/code:1]
One or two of styleclock's themes is numerical/digital as well. Much easier to read than the default kde clock, no matter how small... here's a snapshot.