After installing ltsp-4.1-r1 you can't customize the keyboard settings in /opt/ltsp-4.1/i386/lts.conf (XkbModel, XkbLayout and XkbSymbols) because the Xserver never loads the keymap giving the error "Couldn't load XKB keymap, falling back to pre-XKB keymap" and falling back to an "us" keymap. After updating ltsp to the latest packages (4.1.1) with ltspadmin everything worked out of the box.
see bug 123721
Re-assign wrt Bug 23545, maintainer retired.
package.masked for security bug 142661.
(Proxy) Maintainer changed. Warwick, your turn now.
Hmm, old package. Not in tree anymore. Please see: bug #177580 - ltsp-5