If you are going to go multi-VLAN data plane (as opposed to multi-label) then 10A will cause you scaling issues as you'll need multiple BGP peers (or static routing),
I'd prefer to use http://tools.ietf.org/html/draft-kulmala-l3vpn-interas-option-d-02 which already has implementations, i.e (albeit differently named) http://www.cisco.com/en/US/docs/ios/mpls/configuration/guide/mp_vpn_ias_optab.html Dave.
