Creating ASP Code Fragments 'on The Fly'

I'm trying to give my clients a bit of extra controll over their application by allowing them to modify parts of my ASP program using a code template. For example, on the landing page, the program displays a list of all current tasks in the user's ToDo list, but different clients may want to handle specific items in that list in different ways: e.g.

Client 1 wants to highlight the oldest items in a different color. Client 2 may want to Alert. Client 3 wants to kick off a message through Email. Client 4 wants to force the user to attend to any messages older than 4 days.

Rather than create a completely custom page for each client, I want to keep the original page exactly as is, but allow each client to configure additional code that will be inserted into the page on load.

One way of doing this is to use Include pages, but I can't use this in this case because there may be several clients hosted on the same server, plus the clients would need FTP access to upload their own include files.

I could also handle most situations in JavaScript, such that the ASP file just writes out the Script block as its loading, but there are some things that are only possible in ASP.

I would prefer to handle this through a database entry which the client can make in their profile page, and then smack the code from the database into the ASP file as it's being requested.