A queue system?

[eluser]brainer[/eluser]
This isn't necessarily a CodeIgniter question, but:

Basically I'm looking for a queue where I can add user_ids to, then processes this queue via cron.

I thought Amazon SQS was a potential solution, but it seems really slow + only allows 10 items to be fetched from a queue at a time. So it doesn't really lend itself well to working with large amounts of data.

I was considering creating my own queue system based on MongoDB, but I'm wonding first if anybody knows any other already available solutions? Maybe one with a nice CodeIgniter implementation?