Well, that's what we called our increased timescale miniaturization internally. The exact amount of time you'll see on the Gantt will depend on the width of your monitor-- we can compress time but we cannot change the laws of physics :).
For instance, if you have a 23-inch monitor and you go to 'Full Screen' mode then you should be able to see a five span for the Gantt chart. We received this request from construction companies and governments (which surely can't be a coincidence) who often manage projects spanning many years. So as of version 1.0.107 these customers will be able to see the even bigger picture.
We did update the presentation just a bit as well to handle the new zoom factor. For example, here is a project in the default zoom:
As you can see this projects extends well past the timeframe for this view. However, if we slide the 'zoom thumb' all the way to the left, we see the project easily fits within the display:
Notice that at the highest level, the 'major calendar' section shows the year and the 'minor calendar' section shows the half year. We shortened this to H1 for the first six months and H2 for the second six months.
Everything is vector-based of course so there is no perfomance penalty for any zoom magnification level you may choose. And naturally the larger the monitor and the greater the number of pixels the more time we can fit on a page. So, if you really need to see a decade worth of project tasks in a Gantt Chart, you have the justification needed to request that super-thin LED 46-inch monitor.
Or just let us know if you need the 'Decade Zoom'. Either way, we're happy to help.