Open source DCIM stack?

Our 500-server data center is growing quickly and my manager has started investigating using a specialized Data Center Infrastructure Management (DCIM) package to help manage constraints.

DCIM software aims to do everything: capacity planning, asset, config, change management, power & cooling monitoring, network monitoring and alarms. Some of the products she is looking at are dcTrack, DSView & nlyte. They are all proprietary and (IMO overly) expensive. Has anyone had experience with these types of systems?

We currently use Nagios, Cacti & RANCID extensively. We need to improve asset management including tracking cabling - the other DCIM feature my manager is sold on is being able to model power & cooling requirements by dragging servers between racks.

My position is that we are most of the way there with the tools we have and DCIM with all its bells & whistles is not good value, and will force us into inflexible practices that aren't necessarily best for us - not to mention vendor lock-in.

So what other practices, processes and OSS tools can you suggest to help manage a growing small-mid size data center?

I am one of the co-founders for Device42 and we are working on creating a comprehensive DCIM solution, that is not OSS but won't break the bank and there is no user lock-in, we allow easy export of data out.

We don't have power and cooling integration yet for racks, but are working on APIs that would let users add/update data using external scripts/programs. Please check it out and we would appreciate any feedback.

Have you looked at OpenQRM? It doesn't explicitly list cable management, but it seems to have the rest you are looking for.