It was suggested in the “Long term connection stability” thread (http://forums.electricimp.com/discussion/comment/728#Comment_728), that more detailed control on WiFi Roaming behaviour would be coming in a future release.
Would this include that fact when a connection is lost or a stronger signal is found, that the impee can then connect to this new AP? I am assuming that the connection would be done based off passed WiFi history connections or a preferred list that could be programmed at runtime and/or at BlinkUp time.
This will allow you to set the trigger level at which the imp will start looking for better APs. You’d get a link down notification when the current wifi was dropped and a link up notification when it had successfully reassociated.
Right now, the imp only attempts to reassociate when the signal is totally gone - and you don’t get notifications.
This is a slightly different angle on the multiple wifi AP configs; mainly the stuff above is related to roaming amongst APs with the same config, but would extend to multiple AP configs when that feature exists.