Preheat oven to 350 degrees. Grease a 2 quart casserole dish. Cook pasta according to package, drain and set aside.
Melt butter in a large saucepan over medium heat. Add green onion, cook and stir for about 2 minutes. Add flour cooking and stirring about 2 minutes. Gradually add half- and- half. whisking constantly until mixture begins to thicken. Whisk in mustard and red pepper. Season to taste with salt and pepper.
Remove from heat and stir in 1/4 c. cheese until melted. Combine crebmeat, artichokes, and pasta. Pour into prepared casserole dish. Add sauce mixture and stir until blended. Top with remaining cheese. Bake 40 minutes or until hat, bubbly and lightly browned.