We have a small number of projects where we expect the client will not be maintaining the installed versions of applications we install to power the site (such as Drupal). Given that an important part of security is keeping things updated, we don't want to host these projects on our Plesk-powered dedicated servers that currently host lots of our other client's websites.

Our goal is to find a host where we can deploy isolated instances (be these slices, virtual servers, grid servers, etc) for each individual (or groups of 2-3) web sites as we need them. These instances would be completely separate, so that if one web site were hacked it would not impact any other site.

Typical hosting requirements:

• Linux
• Apache
• PHP 5
• MySQL
• Supports Drupal
• Ability to setup a cron task (but we don't need SSH access)
• Daily backups
• Virtualized/cloud hosting (we want to avoid shared)
• Pricing per site is around $25/month
• OS is patched automatically

Some options we have considered but won't work:

• MediaTemple: Two major data center-wide security incidents and recent downtime foster doubt about this host's technical ability.
• Slicehost: This would require us to manage the entire server, which we don't want to do.
• Rackspace Cloud Sites (formerly Mosso): No backup options.

Do you have any recommended hosting options for given these requirements?