Question: Is there a way to create custom delegate control in sub-sites without having to restart the IIS server?
I have full admin/SharePoint designer access to the sub-site, just not the IIS installation.

Also Is there a way to obtain the parent site WSDL asmx without having access to the parent SharePoint site, but having full control of the current sub-site?

I never see the option for the Style Library or the \_layouts/\_vti\_bin folders to be created.
Can anyone shed some light on these items and how they can be obtained/copied to the parent folder without having access to the parent folder?

Answer: 
i havent tested this, but as long as your delegate control is placed in partially trusted location (bin) and not global assembly cache (GAC) i cant see why it shouldnt work without an IISRESET. But i would have to test it to be sure. EDIT: ok chris piped in with his answer while i was writing this. He sounds kind of convincing, so he might have a point :-) 

The web services can always be reached through the /\_VTI\_BIN/ virtual directory from any subsite since its a vdir on the virtual web on IIS
I think I have seen scenarios where there is no need to iisreset/recycle app pool with delegate controls.

Perhaps it matters whether it's an assembly based control vs ascx based control or as Anders mentioned, whether it's in the GAC vs the bin.