Hi Henry

    - The "Select Keyboard Model" window is unsorted, which makes it
      hard to search.

I'll fix this
 

    - I cannot find my currently listed Keyboard Model, "evdev". Should
      it be in that list?

The list of keyboard models, keyboard layouts+variants and
keyboard shortcuts to change layout are imported statically from xkeyboard-config.
xkeyboard-config lists all the options to be feeded to setxkbmap (which is the only dependency)
If you feel that an option is missing try it and then provide me neme (e.g. evdev) and description
and I'll add it to the list.
 

    - The German and US flags seem to have different sizes. Is that on
      purpose?

I'll fix this.

    - When using text layout, and putting the mouse over the plugin, the
      background becomes almost white, with white letters. This is very
      difficult to read. (I guess this was already the case with the old
      plugin?)

Yes I didn't change anything of this, but I'll try to reproduce the problem
as it never happened on my lubuntu 12.04.

A patch to the git repository [1] would be easier to handle, since all
the files added by the autotools generate a lot of noise. But it is ok
for now.

> the only changes that I made are to lxpanel-0.5.10/src/plugins/xkb/*

Actually, I saw a change outside that directory, too. Would be great if
you could point out if there are more.

with meld (http://meldmerge.org/) you can easily spot the differences
between the two

lxpanel-0.5.10/src/plugins/xkb/*

forget about the other changes you see that are from the ubuntu patch,
the only one that I added is this in lxpanel-0.5.10/configure.ac

@@ -40,6 +40,7 @@
 pkg_modules="$pkg_modules \
              gio-unix-2.0 \
              gthread-2.0 \
+             alsa \
              libmenu-cache"
 #             libstartup-notification-1.0"
 PKG_CHECK_MODULES(PACKAGE, [$pkg_modules])

I believe that alsa should be added to the dependencies since the plugin
volume works bad and requires to load manually a kernel module,
volumealsa instead works good but is built only if the header files are found
(libasound2-dev on lubuntu)

> The flags are in lxpanel-0.5.10/src/plugins/xkb/flags/*.svg and are taken
> from xfce4-xkb-plugin.

Should give them proper credit in the AUTHORS file. I assume the license
is ok?

The first svg flags are from the flags folder of xfce4-xkb-plugin which are GPL,
xfce4-xkb-plugin is anyway already credited since the original "keyboard layout switcher"
comes from that

Other flags are taken from http://hewgill.com/flags/ or https://github.com/koppi/iso-country-flags-svg-collection/tree/master/svg/country-4x3 or wikipedia,
they should probably be credited as well.

I will write again when I'll have the reported issues fixed.
Regards,
Giuseppe.