I have the same exact problem. Started with the upgrade to Kubuntu  13.10 (Saucy). I recently started running Kubuntu 14.04 (Trusty) in /devel form and continue to have this problem. My Country/Region & Language looks exactly like Steves screenshots posted on the Kubuntu forums. I would also like to point out that I have no currency symbol (blank and no choices). 

Mirroring Steves info:

pat@Pats-Main:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu Trusty Tahr (development branch)
Release:        14.04
Codename:       trusty

pat@Pats-Main:~$ uname -a
Linux Pats-Main 3.12.0-4-generic #10-Ubuntu SMP Thu Nov 21 22:07:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

pat@Pats-Main:~$ kded4 --version
Qt: 4.8.4
KDE Development Platform: 4.11.95
KDE Daemon: 4.11.95

pat@Pats-Main:~$ locale
LANG=en_US.UTF-8
LANGUAGE=en_US:en
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

pat@Pats-Main:~$ locale -a
C
C.UTF-8
en_AG
en_AG.utf8
en_AU.utf8
en_BW.utf8
en_CA.utf8
en_DK.utf8
en_GB.utf8
en_HK.utf8                                                                                                                                                                       
en_IE.utf8                                                                                                                                                                       
en_IN                                                                                                                                                                            
en_IN.utf8                                                                                                                                                                       
en_NG                                                                                                                                                                            
en_NG.utf8                                                                                                                                                                       
en_NZ.utf8                                                                                                                                                                       
en_PH.utf8                                                                                                                                                                       
en_SG.utf8                                                                                                                                                                       
en_US.utf8                                                                                                                                                                       
en_ZA.utf8                                                                                                                                                                       
en_ZM                                                                                                                                                                            
en_ZM.utf8                                                                                                                                                                       
en_ZW.utf8                                                                                                                                                                       
POSIX  

pat@Pats-Main:~$ localectl status                                                                                                                                                
   System Locale: LANG=en_US.UTF-8                                                                                                                                               
       VC Keymap: n/a
      X11 Layout: us
       X11 Model: pc105

pat@Pats-Main:~$ localectl list-locales
C.UTF-8
en_AG
en_AG.utf8
en_AU.utf8
en_BW.utf8
en_CA.utf8
en_DK.utf8
en_GB.utf8
en_HK.utf8
en_IE.utf8
en_IN
en_IN.utf8
en_NG
en_NG.utf8
en_NZ.utf8
en_PH.utf8
en_SG.utf8
en_US.utf8
en_ZA.utf8
en_ZM
en_ZM.utf8
en_ZW.utf8

pat@Pats-Main:~$ localedef --list-archive
en_AG
en_AG.utf8
en_AU.utf8
en_BW.utf8
en_CA.utf8
en_DK.utf8
en_GB.utf8
en_HK.utf8
en_IE.utf8
en_IN
en_IN.utf8
en_NG
en_NG.utf8
en_NZ.utf8
en_PH.utf8
en_SG.utf8
en_US.utf8
en_ZA.utf8
en_ZM
en_ZM.utf8
en_ZW.utf8

pat@Pats-Main:~$ cat /var/lib/locales/supported.d/local
en_US.UTF-8 UTF-8

pat@Pats-Main:~$ dpkg -l | awk '{print $2}' | grep lang
language-pack-en
language-pack-en-base
language-pack-kde-en
language-selector-common
liblangtag-common
liblangtag1
libslang2:amd64