so what is security like on the eurostar and TGV? I'm assuming it will be greater on the eurostar. How similar is it to an airport? do your bags get x-rayed? How extensive is the search? Last time I used the shuttle which is quite different and it has been a long time since I have used eurostar. Any help/ideas?

No clue, all I know I've seen narcotics officers with dogs often in the Central Station in Amsterdam. (few times a month)

I've set one off actually, I used to take the international train to Paris to travel inside the Netherlands (it has two stops before leaving the country).

well if anyone cares:

I don't know about TGV yet but eurostar has rather tight airport like security at the
English end and slightly more lax security at the other.