Another (free) monitoring/help desk system that I wont name is offering a check of the warranty/support status based on the Service Tag of the machine and send a reminder prior the Service contract expiration. That would be a nice feature in WHD.
Major vendors provide API:
- HP: http://stackoverflow.com/questions/8451516/is-there-an-easy-way-to-lookup-warranty-information-for-dell-hp-servers-someth
- Dell: Support Services APIs
- Cisco: https://apiconsole.cisco.com/supportapis
I'm sure there are many more...