Lpc2000

If you had a transfer vector (an array of library entry points) at a 
fixed location and all of the proprietary code called library 
functions indirectly via the vector, you could just provide your 
object code and the location of the vector (leaving space for 
expansion, I suppose).  If the customer upgrades the library the entry 
points in the vector change but the library is never actually 'linked' 
into the application.  There is this clear line, the vector, where 
LGPL/GPL code is separated from proprietary code.

I'm trying to get at the functionality of a dll in an embedded 
environment.  It's a little tough...  But the idea is that the 
proprietary stuff is shipped as a pure binary 'block' and the linker 
never really needs to know what is inside - just where the transfer 
vector should be placed.