I think you can still do the super-backer thing. They apparently re-opened the sign-up form. Check the Kickstarter backer updates for The Tower.
Yeah, I asked on the KS comment page and was informed of the good news. The first thing I did was try the online form and while it did load, I couldn't interact with the text fields, so I assumed iDGi was no longer accepting submissions. Auto-filling the field with the help of LastPass did the trick, though. Strange bug.