Haveing a problem with large file uploads on IIS7. Are you finding that regardless of what you do the  <httpRuntime> setting are being ignored? Well I did and here's the anser - thanks to a Telerik article.

Note that this does not require the "RadUpload" component to work - as featured in the  original article.
http://www.telerik.com/help/aspnet-ajax/upload_uploadinglargefiles.html

[Web.config] Web.config settings for 100MB and 1 hour
<configuration>
...
<system. web>
  <httpRuntime maxRequestLength="102400" executionTimeout= "3600" />
  ...
</system .web>
</configuration>  

Settings for IIS7

Add these lines in the web.config file:

[Web.config] maxAllowedContentLength attribute for IIS7 
<system.webServer>
...
   <security >
     <requestFiltering>
       <requestLimits maxAllowedContentLength="1024000000" />
     </requestFiltering>
   </security>
</system.webServer>

Open the file C:\Windows\System32\inetsrv\config\applicationHost.config and find the line:   

Set the overrideModeDefault property to Allow.
<section name="requestFiltering" overrideModeDefault="Allow" />