Even with VDSL you will have problem, if you have more than 800m from node then you are not able to have a VDSL and even you have VDSL you will never get 50MBps
(That's the 'rules' of OTE [greek company wich provide Internet)
About the REAL distance of VDSL...
250 Mbit/s at source to 100 Mbit/s at 0.5 km (1,600 ft) and 50 Mbit/s at 1 km (3,300 ft), but degrades at a much slower rate from there, and outperforms VDSL. Starting from 1.6 km (0.99 mi) its performance is equal to ADSL2+.