Hello Christian,
Unfortunatelly VPLS support depends of the linecards installed in 7600/6500
We have the same problem. We have a lot of 7603 routers with SUP720 or SUP2 in our small POP' and need to deploy VPLS saving capex.
The sup2T is supported only on Cat6500E chassis so I don't think you could upgrade your SUP without a new 7600/6500E chassis.
I'm trying to collect information about the old OSM 7600/6500 GE modules like the OSM-2+4GE-WAN+ to save CAPEX.
I think they could do VPLS very well for small-PoPs.
I'm looking also for information about QinQ subinterface VLAN termination support on these modules.
Cisco documentation says is supported only on SIP-400 + SPA-GE-V2 or ES+ card