I am confused about your use of tech verbage.  I was always under the impression that when you talked about tech stuff being federated, it generally meant clustered, like 3 servers are federated with 1 being the parent or main.  Also, you are wanting spark to communicate with your bb, it doesn't really work that way.  to connect to any IM network (jabber, irc, yahoo) you need a client.  spark is a client and openfire provides the jabber network.

So that being said, you need a client on your bb, not spark talking to your bb and then to openfire.  you need a client on your bb to talk to the openfire server.  it has been said in this forum spark will never be developed for the bb, so thats out.  so you need another client.

there are a good number of multi protocol clients that work on the bb and can talk to a jabber server, most however require your jabber server to be exposed to the internet.  the paid for clients you mentioned in your article work with a BES and so can communicate inside your network already.

I believe the problem is either 1) the use of jabber/xmpp on the bb isn't important enough and widespread enough for there to be a ton of developers, or 2) the RIM SDK is expensive and difficult to use (I can't comment on either) making it difficult to even develop apps on the bb.

we have about 130 bb's at my work and I have checked on this and checked on this, and we can't just fork out $30 per phone for folks to use this.  so our stance is to wait until someone develops it or develop it ourselves, which isn't going to happen.