No leak here on a kdenext enabled siduction after a day and a half of uptime (Plasma may be up less than that, but surely more than 7 hours).
I am however getting Plasma crashes every few hours or so, which seems to be a known bug:
351492 - Crash in garbage collection.
# apt-cache policy plasma-workspace
plasma-workspace:
Installed: 4:5.4.1-siduction1.4
Candidate: 4:5.4.1-siduction1.4
Version table:
*** 4:5.4.1-siduction1.4 0
500 http://packages.siduction.org/kdenext/ unstable/main i386 Packages
500 http://ftp.spline.de/pub/siduction/kdenext/ unstable/main i386 Packages
100 /var/lib/dpkg/status
4:5.4.1-1 0
500 http://ftp.hr.debian.org/debian/ testing/main i386 Packages
500 http://ftp.debian.org/debian/ testing/main i386 Packages
500 http://ftp.hr.debian.org/debian/ sid/main i386 Packages
500 http://ftp.debian.org/debian/ sid/main i386 Packages