[c-nsp] Replacing an obsoleted Nortel/Bay BCN

[Network Fortius]

I need to replace an over-aged Bay BCN, which terminates right now  
all our WAN connections (10 full T1s and some fractional ones - data  
part + a PRI for ISDN backup) with a new router. "Behind" the Bay  
(its ethernet interface into the main campus network), I have two  
6509s in HSRP mode (core and server connectivity), then a bunch of  
4000s connected to the 6509s (access). The replacement router will  
have to be able to handle roughly 24 T1s (I am moving from an "active- 
on-demand" ISDN, nowadays totally insufficient, to multi-vendor,  
multi-T1s per location - all active, and with failover capability  
from one to the other, of course). Part of the T1s will still carry  
voice and data, for which I plan to use something like DI VWICs (to  
move away from the now independent CSU/DSU that do the data and voice  
splitting before the Bay). The router should also be able to support  
VoIP.

Having said all of the above, I was wondering what kind of gear you  
would recommend to start looking into. Our Cisco rep is leaning  
toward a 6506/9, but to me it "looks awkward" to having to front end  
a pair of 6509s with yet another one. I was thinking more of a "pure"  
router, but I am not sure which ones would fit the requirements for  
multi-serial interfaces like I have. Pointers to [RTF]D(ocs) or [RTF]L 
(inks) would be mostly appreciated, as I would definitely have to do  
my homework, with a little direction ;)

TIA,
Stef