Here's an "incomplete" fix. Update and immediately "park" the new apps onto an external hard drive. To do this, create a folder on your external hard drive named "Applications," go ahead and update in the app store, and immediately drag the three or four apps (the new Pages, Keynote, iMovie, and Numbers) from your computer's "Applications" folder onto the "Applications" folder you just created on your external drive. Now your computer no longer has these new versions of the apps on it. Disconnect your external hard drive, and your current and old Pages etc. files will continue to open in old, iWork '09 format, as always. [[Note: you may not need to disconnect the external hard drive; I'm just being safe. Just make sure that when you open a Pages/etc. file that it opens in old Pages (iWork '09), which you'll be able to tell by how it looks on the screen. If it opens in the new one, quit and don't save. Then, single click the file's icon, select "Get Info" (command-i), and choose "Pages" (with the '09 icon) (or Keynote/Numbers/etc.) under "Open with," and then select "Change All" so that all your Pages files will then open with '09 and not 5.0.]] Then, whenever Apple has an update (every few months) for those new Pages/Keynote/etc. apps, your app store badge will alert you (the annoying alert), saying that they cannot install those apps automatically. When that happens, simply connect your external hard drive and the alerts will go away and the app store updates tab will not show those apps as needing an update.
I believe what is happening in this procedure is that your computer is automatically downloading the new Pages/etc. updates in the background, but is not installing them without your permission. Then, when you reconnect your external hard drive, it automatically connects up with it without you doing anything else but connecting the external hard drive.
Not sure about all the tech stuff here, but this procedure should solve the update-badge-every-24-hours problem by making it only occur when a new update happens; then, just connect your external hard drive, and it goes away. Meanwhile, you can continue to use iWork '09 versions in utter bliss. 🙂