Is it possible to store PHP scripts in the cloud?

Yes

Simplest example would be to grab the script from a service, stick it in a variable and eval it.

Could you provide an example of why you’d want to? I can’t think of a good reason to do it offhand.

Absolutely. Check Rackspace or any top hosting service. Yahoo! does it.

@ETpro interesting, could you point me to an example?

Here’s Rackspace’s solution. Yahoo! Stores are cloud based now, and offer not only RTML and proprietary database development, but a separate subdomain with PHP, Perl and MySQL installed.