You can already do essentially that:
http://people.omnigroup.com/dave/link-o-tron.html
Visit the page, type in your action, paste resulting link into an email to a personal account. Read it on iPhone (or Mac) and tap link to add to OmniFocus.
The page does its work locally, too — no data is sent elsewhere, and you could probably just keep a local copy of the page if you don't want to be seen visiting the Omni site. Still a problem if you aren't allowed to send personal email, though. Strikes me that such a company might also be unhappy if you were doing this with work-related information (even though you are trying to increase your productivity).
Another approach would be to use OmniFocus for iPhone's ability to record audio attachments to dictate actions to yourself. Later, play them back and type in on Mac, then delete audio.
I hope other aspects of your job make putting up with this nonsense worthwhile!