I recall one case about 10 years ago. A lady contacted me complaining about not being able to Skype her friends. I looked up her address and she lived just down the road from her local exchange so that definitely didn't sit right with me. Arranged a visit to her house. Arrived at her house and noticed straight away that her modem was located at one side of the house with a long extension cord to the other side of her house where the jackpoint was. Logged into her modem and it was syncing at ~1mbits and performance, even for simple web browsing, was incredibly poor. Convinced her to lose the extension cord and just put the modem next to the jackpoint. Speed at that point jumped up to over 20mbits. She at that point had the fastest ADSL sync speed I had ever seen off the then Telecom network.

So yeah it might "just be another so-and-so meters" but it can easily make a huge difference. If the above can happen on a connection only a few hundred meters from the exchange, imagine how bad it'd be in the sticks.

If you really must do it, I suggest you get good quality extension cord. Your performance will certainty suffer regardless of what cable you get, but a better quality cable will at least minimize the losses in the short term until you can find a better solution.