Here’s my attempt at a PHP London logo. It’s just a bare logotype, but might form a basis for more elaborate designs:
It’s derived from the official PHP logo which is provided as a vector outline. I couldn’t find or identify the typeface – it looks a bit like Eurostile or ProFont (but it isn’t either) – so I redrew the characters to match.
Obviously there is scope for all kinds of arrangements (and not outlining), but at least we now have a "London" in a typeface that exactly matches the logo.
For those that like to twiddle, here is the Illustrator CS2 file (should be PDF compatible, probably need to right click to download it as it has a dumb mime type). The file also includes an uncombined version. Creative Commons License.