Just to throw in evidence to the contrary, I've been able to make trade agreements and have gotten more than two wagons from the humans when trading. Started this fortress with v0.21.105.21a and have upgraded along the way to the current v0.22.120.23a. Fwiw...
Edit:
Oh yeah, I finished the road shortly after the beginning of spring in the second year.
And,
(1) I've had good trading with the humans, not stealing from them and always making sure they make at least a 10% profit since I got the broker.
(2) Yes, I have the broker and a trade minister. I got the bookkeeper after those two. Nothing further than the Mayor yet, but since I'm over 100 dwarves now, I expect to see a few more nobles in this the spring of my sixth year.
(3) I haven't had any trade reps die. I've only lost one member of a trading caravan. That was one of the dwarf merchants from the autumn caravan, my first goblin siege started right after they unloaded in the depot and they were unfortunate enough to be downwind of the goblin archers that were shooting at the war dogs that were on the road. That was enough to make them bail, but the rest of them made it off the map ok since my group of stalwart crossbowdwarves had broken the siege.
/edit
[ December 09, 2006: Message edited by: randomjgj ]