Back to the Original topic.
If you'd like to test flash, (Youtube, games etc.) on the maemo 5 SDK, it can be achieved by the following:

get the Flash Player 10 for Linux (.tar.gz) Unzip it with your favorite archive manager.

Copy the .so file to /scratchbox/users/USERNAME/home/USERNAME/.mozilla/plugins

Restart Browser... Done and Done.

I'm attempting to do the same with the LogMeIn plug-in for Mozilla.

Granted, this won't show the same performance as on device (I would suspect) but at least you can work on interfaces and size formatting.