I've noticed that there are wrappers for a lot of javascript libraries and such, but I have yet to see anything significant for jQuery.
Am I just not searching hard enough and there is one out there? Or is there some problem with jQuery that keeps someone from creating a wrapper?
Are you looking for a jQuery wrapper for the ASP.NET AJAX library, or an ASP.NET AJAX library that wraps jQuery?
There are some server-side ASP.NET controls available that wrap some jQuery effects. http://clipperhouse.com/jQuery/
Also, check out CodePlex as there are TONS of projects hosted there for server-side jQuery wrappers and client-side extenders.
http://www.codeplex.com/site/search?projectSearchText=jquery
Your signals may be a bit crossed here regarding the proper use of JQuery and ASP.NET.
JQuery is a wrapper that simplifies Javascript (in particular, access to page elements). It is a client side technology.
ASP.NET is mostly a server-side technology. While you can place controls on the page that will emit javascript (e.g. control validation) and there are a variety of ways in which Javascript is employed to simplify WebForms development, ASP.NET it isn't really about client-side programming in the same way that JQuery is.
Honestly, I wouldn't want ASP.NET to wrap JQuery as it would just lead to impedence mismatches between how you handle client and server-side processing. Plus, JQuery really is pretty easy.