I thought those instructions were fairly detailed already. Which part are you having trouble with? Parts you need:
-lm317 chip + heatsink
-two 220 ohm resistors
-two 100 ohm resistors
-two capacitors rated for 16v or above. As big of a capacitance as you can fit inside the adapter.
-barrel plug (not sure what size though...just whatever will fit in the mini. I took mine off an old nokia phone charger)
Then follow the schematics in the link. Since it does take a fair bit of time for me to build, I think I would have to charge about $50 each shipped to the US/CAN. They dont exactly sell the lm317, capacitors and resistors single, I have to buy a whole bag. I could probably offer a better price if more people were interested in buying. But honestly, it would be best to build it yourself if you can.