Hi, there are curvature / CRT shaders available for FS-UAE. FS-UAE 1.3 implements XML Shader Spec 1.1 which means that it can use shaders written for other emulators as well, such as bsnes. Recent development versions of FS-UAE include a CRT curvature shader.
There are a couple of screenshots in this thread (one showing a curvature shader, and other showing curvature + CRT effect):
http://eab.abime.net/showthread.php?t=64137