[c-nsp] How to resolve redundancy/fail-over w/non-hot swappable cards in 3845

[Netfortius]

I have a client who has a setup consisting in two fully loaded (with cards) 
3845s - one active, with full T1s, as well as channelized ones (drop-insert 
cards with voice channel going then to the PBX) coming into it (a 
hub-and-spoke setup for WAN links). The problem I am having is with the 
possibility of failure of any card inside that router, as these are not hot 
swappable, thus the need to shut down and interrupt all communications coming 
and going into that router, until replacement, or switch over to the 
stand-by. The issue is that we had experienced, in the past, loss of "D" 
channel on the voice side, which could add to the downtime simply because the 
voice may not come back up properly, and immediately. Add to this the fact 
that I could not find a proper way to utilize an active-active environment 
with 3845s (I was looking into using some sort of Y cable from the T1s, and 
have them all switch from one router, to the other, but nothing seems to be 
working without interruption to the data or voice). The question is if there 
would be any way to create a fully redundant environment, knowing that we 
could have two 3845s identically (hardware-wise) configured, in case I loose 
a card in one of them. I would appreciate any suggestions/links/pointers in 
this regard.

TIA,
Stef