[j-nsp] MX Virtual Chassis?

[OBrien, Will]

I'm curious if anyone has been using MX's in a VC config. It's supported on the new MPC blades, but supposedly not with the older DPCs.
I haven't done any testing yet, just minimal research. 

Why would I want to? Well, I'm after redundancy with my services blades. Specifically, MS-DPCs. I've got a pair of 480s, each with a single MS-DPC.
I'd be hoping to configure rsp interfaces on the VC. 

I'd appreciate thoughts on this. I use the MS-DPCs for my CG nat implementation. I'd rather not buy two more (rather expensive) blades just for redundancy sake. I'm not even sure how much redundancy the availability of the second blade would really provide.

I have the impression that very few people are doing this. I'm already a bit borderline on the speed of response on support questions with TAC since I'm running enhanced SBCs, MS-DPCs, policing a few /16s on a per ip basis along with CG nat.