php-based sftp server?

My webhost adamantly refuses to support an sftp server. Supposedly too much overhead to support all their servers with it. Lots of people have been requesting, too.

So, while I look for a new webhost, I was wondering if anyone has heard/seen of an sftp server created in php. Probably all kinds of reasons it wouldn't work, but I'm curious.

Or, if anyone has a way that I can integrate winscp to connect to cpanel(our administrative backend) that would be cool to.

Thanks for suggestions.

I'm 90% sure that it is not possible. You would not be able to emulate SSH server on HTTP server.

https://github.com/phpseclib/phpseclib/blob/master/phpseclib/Net/SFTP.php
(OK, there are issues...177 open, but 613 closed !)

@kuRyOres: I do not understand your post. First, that's client, not server. And I didn't wrote that you cannot write an SSH server in PHP. But that you cannot implement an SSH server using a PHP script on a web server.

You're right: my mistake, it's a SFTP client!
SOLVED