We're seeking the input of profiler users and other interested parties to help create a visual profiling tool for mono applications. Development is under way in the mono-tools module alongside the current command line decoder. The tool is a UI to interact with the built-in mono logging profiler and graphically display captured profile logs. The visualization capabilities of the tool are still fairly primitive, but it is already capable of creating and displaying log data for instrumented, allocation, and statistical profiles.
I have created a wiki page to track the feature capabilities and plans. There is also a "Visual Profiler" category for bug reporting and enhancement requests in the Mono:Tools bugzilla product. Discussion will occur on mono-devel-list.