This is from version 1.6.0a of XAMPP and lighttpd is 1.4.13 from here.

This is a very primitive release. There are of course problems with it. If you find something not listed or have a fix for it, please let me know.

Usage:
1. Run setup-xampp.bat to update configuration.
2. Run lighttpd_start.bat to start lighttpd.
3. Use the .bat files to start or stop the other components.

Issues:
1. The xampp-start.exe, xampp-stop.exe, xampp-control.exe either don't work, or don't work well. If someone wants to fix these, please do so.
2. Perl, I didn't test, but should work.
3. XAMPP is still shown everywhere instead of XLMPP. Meh.
4. No installer
5. Only for Windows
6. Doesn't work on Vista, or shouldn't, since lighttpd doesn't.
7. Setup changes lighttpd.conf even if you don't select 'Refresh XAMPP'.

Changes between XAMPP and XLMPP:
1. lighttpd directory added.
2. lighttpd_start.bat and lighttpd_stop.bat created
3. apache_start.bat and apache_stop.bat edited to start lighty instead
4. install.php edited to edit lighttpd.conf. (lines 57-68)
5. apache directory deleted.

Download:
Download XLMPP in ZIP archive (75.6 MB) This was removed for being outdated.
MD5: 362ff2b7366d3457061d3e7d8f2098a2

Download lighttpd + XAMPP->XLMPP files (3.68 MB)
MD5: 382d8ff96c83294dd40879dbcc506663
You need some version of XAMPP. Extract this archive into that folder, overwriting existing files. Run setup_xampp.bat. Start lighttpd by running lighttpd_start.bat. (Note: This lighttpd is probably outdated now)

(XAMPP + lighttpd) -> XLMPP files (10.2 KB)
MD5: 2e39627fe17c612f5880f7b93971e4ce
You need a version of XAMPP and lighttpd. Copy the lighttpd directory into the XAMPP directory. Extract this archive to the XAMPP directory, overwriting existing files. Run setup_xampp.bat. Start lighttpd by running lighttpd_start.bat. This includes the new batch files, new install file, and a new lighttpd.conf.