We need a PHP Cron Management Script

We have a web application that runs a number of crons for each account. We presently use a service called Webcron to manage these crons however as we go into production with the web app, it's no longer suitable.

We're going to set-up a linux server (AWS EC2 instance) virtuously to handle the crons (there will be hundreds plus) and each cron calls a script using wget. Each cron differs in time from once a day to every 2 minutes.

When a fresh account is created our application automatically creates the cron jobs.

And so we want the following;

1 - Framework for control a large number of crons. Maybe every 'account' has a cron file? Or if just one file a structured approach to seeing what's in the file.

2 - A cron Client class (PHP Script to act as api to handle requests from our application. Namely-

a) Create new crons (our app will supply the variables - name, url, time etc)

b) Remove cron

c) List crons (and their attributes).

d) Error notifications (email is fine)

Desired Skills are Linux, PHP