I wanted to share this with the larger community. I was able to get perfect subpixel rendering on my 11.2 install for GTK apps in KDE (I've tested this on GNOME as well- it works fine).

Steps to enable subpixel rendering:-
1. Install the freetype2 packages from Index of /subpixel

2. I have a patched cairo located in my OBS repo at Index of /repositories/home:/anshuljain/openSUSE_11.2/i586. Install the cairo package. This patched version differs from the earlier patched versions in Index of /subpixel. I have enabled the original LCD patch, which looks a LOT better than the previous cairo patched builds in the Supixel - openSUSE-Community repo.

3. Create a file 10-lcd-filter.conf in /etc/fonts/conf.avail as, and copy the following contents :-

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<!-- Enable freetype's new subpixel filter. Currently, only a cairo
version containing the patches from freedesktop #10301 respects this
setting. -->
<match target="font">
<edit mode="assign" name="lcdfilter">

4. Create a file ~/.Xresources in your /home directory and paste the following contents:-

Xft.lcdfilter: lcddefault

5. Log out and login again.

Now for the necessary screenshots