Web interfaces, z39.50, and opac providers

[The Big Glee Bopper]

I'm working on a small project which seems to be developing an 
interesting approach to information filtering for a public library 
connected to the net. A major problem is not with the net interface but 
with the interface to the opac. This organization is in the process of 
securing another opac provider but what we need is a provider which will 
provide client/server support where the server manages the opac and we 
are provided with the needed support to integrate the opac completely 
into the library interface to the extent that you never even know you are 
querying geac/notis/innovative/dra/etc.

Anyone have any experience with such a provider? Would really appreciate 
phone numbers and names.

--Thom