Content Management Software - Build or Buy?

WallyHartshorn asks: "I'm the web coordinator for an agency (1,200 employees) with a web site consisting of roughly 2,500 static HTML pages, plus a few hundred Acrobat files, a dozen CGI scripts, etc. Currently, updates are done manually by a staff of 2 full-time web developers (including me) and 5 non-IT employees who have web page development as about 25% of their job responsibilities. We have been considering purchasing some web content management software, probably something on the lines of RedDot, eMPower, or Microsoft Content Management Server. We've also been considering using Zope or building something ourselves from the ground up. We only have two Perl programmers and nobody knows Python. Given the current budget limitations, we might have more luck getting permission to spend a few months writing our own software than we would getting approval to spend thousands of dollars on a pre-built package. On the other hand, I could also see a "build from the ground up" project turning into a maintenance nightmare. What experiences have people who run web sites of a comparable size had with building their own web content management software versus purchasing one? (Please keep in mind that we are not running a blog, a news site, or a community site, so something like Slash would not work.) Our content consists primarily of reference material and services.)"