There may not be an ideal single device solution. Most devices tend to max out when confronted with the highest VDSL2 line speeds. Currently, the mots powerful series of VDSL2 SoC is Broadcom's 63xx. Although in some condtions, the Lantiq VRX200 series can outperform the Broadcoms in raw line speed. For optimum performance, it's best to use the modem, whatever its chipset, in bridge mode, coupled with a separate router for the pppoe layer, firewalling, NAT'ing, etc.
Have a look at the available VDSL2 CPE chipsets. At the last count, there were surprisingly few on the market.
http://forum.kitz.co.uk/index.php?topic=11470.0
cheers, a