Approvals tracking (Score 1)

You're not really looking for full-blown document management. You're looking for electronic approvals (usually called eSignatures).
The simplest way to do it is embed the eSignature (approval) in the word document or in a pdf.

Look at silanis for embedding in word documents
    http://www.silanis.com/solutions/e-signatures-desktop.html
Look toward adobe for embedding in pdf.
    http://www.adobe.com/products/livecycle/digitalsignatures/

I would only use these for the important approvals that legally require signatures. For anything that's just an out-of-date internal process, consider something simpler. (eg. email approval is good enough).