You don't look at the ATM protocol. You look at your router. If you want a modem that will support 100 Mbps, then a small router like 890 (as an example) won't support this speed.
You need to have a big router, like a 3945 to support 100 Mbps. That is, of course, you can find an EHWIC card which will support vectoring. Currently, there's no Cisco modules available to support vectoring. Don't know when it'll come out. I guess Cisco is still listening out to see if it's worthwhile developing something like this.
