Who has experience with managing large image sets?

Dear all knowing beeb:

Can anyone recommend a good software tool for digitial asset management? I am especially interested in workflow management and version control.

I need to find a management tool for digital assets that are mapped to physical product codes. The base set is about 24,000 items mapped to 6000+ SKUs. Now we are starting to introduce image sets sharing from the same pool but with different branding, and spread across different content management systems. The little version control we have comes from Excel records and prepending filenames with dates.

I have found what look like excellent packages, but with the typical "call for quote" pricing. In my experience this will result in something like $ 2000 per license per named user with a 20% maintenance fee. If the other alternatives suck, I'm willing to do it. Can anyone recommend any particular packages, or have any particularly clever ways of handling these problems without specialized software? I would strongly prefer desktop software over SAAS as we host our images on an on-site server, and I don't want to deal with bandwidth issues as we have shit internet.