Hey Patrick,
The interesting (and at times annoying thing) about the front caster is that it doesn't actually completely touch the ground, which allows Eddie to rock back and forth a bit between the front and rear caster. Since my current project is intended to run on a very flat surface, I may actually extend the caster so that there is no play at all; it'll be interesting to see how restrictive that is.
Yes, the Eddie board just became available as a standalone component a week or so ago. It is a bit pricey--I'm not a hardware expert so I'm not sure where the cost would come from, but I've definitely seen that the higher-power motor controllers get very expensive (and without all the capabilities of the Eddie board).
And you're right--I think a wrapper for ROS would be an excellent project. On the surface, I don't see any reason why one couldn't be written.
Arthur