In the Core database (you can switch using the icon in the bottom right next to the clock) you can go to /sitecore/system/Settings/Html Editor Profiles/*profile you want*/buttons/HTML view
and deny read-access on that for your users. Alternatively, at least in Sitecore 6.5, there's a profile without the HTML view. It's called Rich Text IDE. You can set the datasource field of a Rich Text field to that one, and not have the HTML view.
That's only removing the HTML option on the bottom left though, I'm not sure how to remove the Edit HTML option you have before you've opened the RTE itself (where you have Show Editor/ Suggest Fix / Edit Html). Looking at This question it might be you'll have to change the XML anyway.
The way we've got upgrades and different instances handled is by having the changed file in source control, and making sure we include it when building a deployment package.