Been there, Done that. The IEPG web page (currently not visable)
has the earliest version I know of, the dGIX (circa 1991-1992).
This idea was implemented in the NSF ATM NAPs (AADS and PB) in
1994-1995. These continue to operate.
The largest problem is where there is apparent layer 3 reachability
but the NLRI (Network Layer Reachability) is fragmented.
The easiest way to "fix" this is to ensure that there is a full mesh
in the ATM cloud. Doing so is not always trivial.
--bill