For what it's worth, I have tried that exact thing on more than one occasion and it works perfectly. The failover was relatively quick, as well, though not as quick as if Rapid Spanning-Tree were supported on routers (hint, hint Cisco).
Whoever told you that the BRI will show as Layer 1 DEACTIVATED when it's in backup mode is wrong. Here is the result of a show isdn status on one of my routers that is configured almost exactly like yours:ISDN BRI0/0 interface dsl 0, interfa...
While I cannot vouch for your madness or lack thereof ;) , I really don't think anybody has a good answer that I can find anywhere. The only thing to note is that the first address you mention is reserved by the IANA. I can only imagine that there ...
Your thinking is correct. When you configure a bridge group (something like "bridge 1 protocol ieee") you are configuring the spanning tree protocol at that time as well. I have implemented just what you mention with the bridge group added to the e...