These lineart animations are 100% coded in actionscript. Compared to doing the work on the timeline it is a lot quicker to do it this way. I remember doing (attempting?) this type of thing in the flash timeline back in the flash 4 days. I rarely use the timeline for animation now. The site logo animation in the header above is also a fully coded animation. The actionscript 2.0 example below only shows a couple of configuration options, the animation itself is less than 10k. (The swf here is larger than that  - its around 43k because of the button and numericstepper components).

I'd seen this type of effect a few times in online advertising where the outline of a product image is traced before the image appears. And I was recently called on to create a full screen lineart animation of a building for a website splash page intro. That work involved creating not only the flash animation, but also the initial vector graphics from tracing/outlining a digital photograph* and a fair amount of research to work out the best way to do it in flash. I've set up my own workflow to quickly do this in actionscript 2.0, so its player 8 compatible (player 7 is also possible). I could easily create actionscript 3.0 versions of the animations as well. And the work would usually be quite quick if your artwork already exists in a vector format. Different effects are possible with masking, fills, image fade-ins and use of bitmap filters. I have some other ideas I want to try as well....

I'm going to explore some different effects/examples and post them here in the near future. For now, if you want an animation like this done for free - for example a logo or product image, and you don't mind me profiling it in my site as an example, please feel free to get in contact (via the contact page). This is a temporary offer, will depend entirely on whether I deem your request to be reasonable, and will disappear soon.

*Unfortunately using bitmap tracing routines wasn't an acceptable approach to doing this part of the work and I did the bitmap tracing entirely 'by hand' using vector drawing software outside of flash, after removing some unnecessary detail and correcting the perspective in the photo. However I will post some demonstrations with automated bitmap tracing so that you can take a look at the effects that can be obtained with minimal effort to create a vector image from a bitmap source.