Domino Utility Server - Antivirus strategy question

We’re thinking about deploying a web app on a Domino Utility Server for a few thousand users. None of the Antivirus software vendors that I spoke with (McAfee, Symantec, Trend Micro) appear to have a general ‘server’ licensing option available for situations where mail will not be utilized. We need an AV scanner to check any attachments that are uploaded, but want to avoid the hefty per user fee for the products.

Does anyone know of a Domino AV software vendor that utilizes a licensing model that’s not priced on a per user basis? Any suggestions/alternative ideas welcome.

Thanks!