Demo ASAP - but as for a date it's very hard to tell, I have a bug list from testers that I haven't touched in a week and a half and once that gets closed off we have to do compatibility tests which are annoying and time consuming. In addition, the current build only supports medium and high display values, we've pushed ahead since the last demo build almost two and a half months ago with particle effects and increased transitional flair and I haven't gotten around to placing the replacement markers for people who can't handle our, admittedly modest, special effects. Then there's the logistics of it all, and opening up support lines with people who aren't already tightly integrated our testing process - which we have someone setting the path for but it's not something that will finalize without some attention from me.
That being said, it is THE priority for us as having a demo is obvious a huge bonus for the Kickstarter. A "let's play" video is on the burner right after the KS launches, and if we're not overwhelmed we'll be able to tackle the demo finalization during that first week. I'll be able to give you a more concrete answer by the end of the first week.
It's one of those strange situations where the worse the KS does, it will probably get the demo out faster since we'll be able to focus on it. Then again, that's clearly a bad situation for us to be in. Either way, I'll be sure to let you know as soon as I can give a concrete date.
There IS a tester tier, but that won't be immediate either - we'd be rolling you into the tester ranks after the KS closes, much more interaction than just a demo and access to builds as they come out.