Any linux-house admins use APT for internal distribution?

Hey all,

I was just wondering if anyone has leveraged Debian's APT to deliver software/applications/libs on an internal network?

We have a few OSS applications that contain modifications unsuitable for upstream use (thus we run internally patched versions). If I wanted to ensure these applications and their subsequent updates were available to ALL Linux nodes (Debian/Ubuntu) inside the organisation (i.e. authorization isn't a particular concern) could I override the availability of the external application source by way of sources.list positioning?

Or perhaps someone has a better way of achieving this? I'm all ears.

Thanks everyone!

EDIT: I should note, we currently just have deb packages in a global fileshare.

EDIT#2: Perhaps setting absurdly high version numbers is the way to go? Would make tracking the upstream slightly more work (a spreadsheet rather than a version number glance, not too much trouble I 'spose)