For me the last frontier would be a similarly practical, to the point article on SSIS library integration: say create a data transfer sproc that uses SSIS Data Flow task.
It turns out that BOL has a decent coverage on SSIS programming. Good enough to just refer to it. Do make sure to also look in http://blogs.msdn.com/mattm/archive/2008/12/30/samples-for-creating-ssis-packages-programmatically.aspx.
But, what i did not find explicitly addressed was using SSIS programming from within "SQLCLR". After blowing a whole bunch of time it turns out that SSIS assemblies reference a whole bunch of other assemblies, each of them of course to be loaded into SQL Server. I am working on 2005 Dev edition 32 bit (help me God on 64-s...). It is not a pretty picture, and I am not a .NET expert, so the solution was to take all of those .dll-s and place them into C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727 folder. Note that the DLLs come from various sources. Here is the list, sorry, look their locations up yourselves because some depend on SQL Server installation, others - who knows what:
Another rub is that access has to be UNSAFE, including the login that does the installing.
And, finally, the microsoft.sqlserver.manageddts must be installed by a sysadmin and the DB set to TRUSTWORTHY for the ManagedDTS to get installed, this must be created separately before your assembly(ies). This might of course invalidate the whole thing unless TRUSTWORTHY and UNSAFE get miraculously ok-ed by DBAs.