The night before, trim the roasts, then rub a good amount of salt and black pepper on all sides.
When the smoker is loaded up and hot, put the roasts in (a couple on the bottom and one on the top rack).
While the roasts are cooking put the Chevre in a bowl and mix in horseradish to taste, maybe even a little salt. Don't be afraid to add a decent amount of horseradish. Chevre is a great foundation for stronger flavors since it's creamy enough to mellow them out and strong enough to not get overpowered by them. It's also great with the coarse pepper present on the tri-tip.
Cut up the baguettes into ⅓ inch slices and put them in a bowl. Toss with some olive oil for even coverage. Spread the bread on a baking pan and broil very quickly - just long enough to get your toast on.
Head back over to the roasts and pull them out when the internal temperature hits 125°F for medium rare. Let sit for 15 minutes.
Now spread some Chevre on the toasted side of each piece of bread.
Slice one tri-tip roast thinly, perpendicular to the grain (I also cut at a 45° angle) so you end up with a nice pile of beef. Cut some of the bigger slices so that they fit neatly on the bread. Keep the other 2 roasts off to the side and cut them up as guests get hungry throughout the day. Now slap a slice of beef on each piece of bread.