Sure. It's totally feasible to make one in canvas, or just HTML tables and colored divs (like the old 3.X timeline), or use a higher-order charting system like HighCharts etc (probably the way to go).
There actually is a prototype module in the build called 'AsciiTimeline', that dates back from the very beginnings of the 4.0 codebase in early 2008. It is what it sounds like - it draws a little ascii bar graph using "x" characters.
We dont test or support the AsciiTimeline module, in fact its conf file warns you somewhat sternly that it is a prototype, it may have bugs and it's generally not a module to be taken seriously.
Also I just looked and there's a JS error that is currently breaking the selection behavior, so while it will still render the ascii bar chart, the clicks and drags dont work anymore, at least not in 4.1.
That said, if you're asking whether it's possible for a partner or third party to try and write such a module, looking at the JS source of AsciiTimeline and FlashTimeline is not a bad starting place.
We've spent a very modest amount of time and energy prototyping a module that uses HighCharts, and I think it's safe to say that at some point we will probably provide an official non-flash alternative to FlashTimeline and someday FlashChart
