I am Mexican, living and working in Mexico. Interest rates for a house are in the ballpark of 10%. This can be either very bad (on a 30 year mortage, you end up paying back about 3 times as much as you originally borrowed), or very good (early payments go straight to capital and have a disproportionate effect on the total amount paid, specially during the first few years). We also have a government mandatory housing fund, paid by your employer, at 5% of your salary (meaning everybody's salary is 5% less than what otherwise would be, but still).
So, we did the rational thing. We rented while we were young and our careers were taking off, we tried to avoid lifestyle inflation when we got raises, and when we finally bought a house we threw every spare cash we could afford until the monthly interest came out of our employers fully. That happened last December (after sinking Christmas bonuses into the mortage).
So, while it requires discipline, it's not that impressive. In this country, paying your mortage using the plan designed by the bank is the same as making minium payments to your credit card. You just keep paying interests without making much of a dent on the capital.
(How is he able to do that? By working like a maniac, I guess.)
On a $100k 20 year loan at at 5.7% (I know, example), interest paid would be around $67k (so total $167k). By paying 3.28 times more per month ($2300 per month versus the $700 normal rate), the interest paid ends up being only around $12k.
I have a mortgage through Tangerine (formerly ING) and can pay down 25% of the original amount during any calendar year - assuming I have the cash, and feel that avoiding that interest is better than the return I could otherwise get investing the cash.