I noticed that asp.net 4.0 now installs a top-level isapi plugin (in iis6), such that it can inspect every request coming to the server. Should this now allow us to run MVC applications with extensionless URLS and have the aspnet isapi process them correctly without requiring the wildcard mapping (and avoid the performance penalties associated)? I havent found anything written about this yet, and havent had time to investigate. Thanks
found the answer: Link
appears that there are new features in asp.net 4.0 that enable extensionless urls. I need to do more research on this to find out how to utilize it.
Basically it appends /eurl.axd/GUID to each routed request, which then gets passed to aspnet_isapi.dll to be processed. the eurl.axd is then removed at this point.
The problems Im having is how these interact between my Ionics rewriter IIRF software and this new .net rewriting... they seem to be interfereing with each other at times.