I like some of these idea. The latest filename thing isn't bad and should be doable.
Re: the /index.php/ thing
While I do agree it is fugly I'm not sure if removing it is the best thing. The download page allows you to do
http://download.simplemachines.org/index.php/filename.extension to get the file. This is easy enough to handle because it will go through index.php regardless. The apache trick basically does a "if the file doesn't exist and the directory doesn't exist rewrite the url" but that could cause problems if I have a file in same directory as index.php and is also a downloadable file. I don't know for sure if that case is present now or is likely in the future, so I'd need to do some evaluating.
The alternative of course is to replace /index.php/ with something like /files/ but then is that really any different?
