I've been adding some research about the IL doing some research about the IL doing some research about the IL basics on Mono, and I just got working the creation of the IL for a Enum using System.Reflection. The problem about my latest approaches was the fact that a special field called value__ must be added to the class.
Based on that, I'll be coding the System.Reflection.Emit.EnumBuilder class. I don't think is will represent a challenge, and the only important thing will be compatibility with .NET.
Also I was reading about parametric polymorphism (aka generics), that represent an interesting approach to the collections that Mono/.NET currently support. The fact behind this feature of C# 2.0 is the posibility of having dynamic collections, like a Stack or a Queue, of the exact desired type. Thus you won't have to use objects as the fundamental unit, avoiding the runtime casts (that cause a lot of runtime related problems and hard to catch).
I will be writing two articles: more about p/invoke, and other about GC in Mono (and good practices).
Finally, right now I'm taking a break with Mauricio. Cool.