[asterisk-users] Zero time (nearly) call transfer.

[Karl Fife]

If anyone would critique this method to achieve the following I'd be
much obliged:

THE EASY PROBLEM (solved):  
1. I am the called party. 
2. Call comes in and is answered by one of several endpoints
3. In the event that the call was answered by endpoint X (x being a
local channel, dialed with the T option), the call can be transferred to
an alternate endpoint by pressing the DTMF sequence as configured in
features.conf
Simple enough...

THE HARDER PROBLEM (unsolved):
Ideally, I'd like to accomplish the same thing but make the transfers
instantaneous and near completely transparent to the calling party by
doing something like this:  DTMF sequence is pressed by called party,
which triggers asterisk to establish a second channel to the alternate
endpoint in advance.  When the alternate endpoint answers, the calling
party is 'switched' to the alternate endpoint, and the endpoint is
dropped.  In other words, a user wants to switch endpoints (usually
wireless to terrestrial, or wireless-to-wireless) without troubling the
customer--eliminating the "Hold on a sec while I transfer you:
click--pause--ring--ring--hello?--OK--As I was saying..."
 
I was thinking of a meetme conference and somehow triggering the drop of
the first endpoint upon joining of the second endpoint.  OR establishing
the second channel connected to a park position, and then quickly
transferring the call to that park position eliminating the call setup
time.  Could someone critique these methods?  Can anyone think of a
better way to do this?  Is there an essential element here I'm missing
that would make this impossible?  

I'm sure that with all the extremely clever people here, someone will
have a good idea.

I appreciate your help!
-Karl