This certainly touches base with the other thread about CRM's.
There are ton's of programs out there that you can manage Vendor Relationships with. Auto-order products when stocks get low, etc.
Everything you need to track can be done in most CRM's by adding the information into each Account, or Contact, etc.
If you're looking to retain reporting features, again, many of the CRM's allow you to create custom reports, that you can create custom fields for, and at that point the sky is the limit really.
For example. The CRM tool that I use allows me to create custom fields on tickets. So I have created lot's of handy fields like: Time On-Site, Diagnostic Charge (check box), Master Ticket, Client #, Support Plan "X", etc. I love being able to customize a field so that I can get the information that I need, into each individual ticket...I hate having to search all over through ticket's to get the details.
For what you're needing I would grab a decent CRM, at low cost, and customize those fields to suit your needs. Then I would create a custom report that I can run once a month or something, to list each of those custom fields, per customer/account, and bam...Now I'm ready for month end inventory check-lists, and auditing.
If you need help let me know...you're not too far away from me!