Since my current DSL modem was crashing at least once a day, I decided to go and replace it after only 14 months. I didn't have much choice available on the market, but I purchased a D-Link DSL-300T (not available in USA). Surprisingly (or not) it runs Linux as firmware and when you open the box, the first thing you see is a printed GPL license.

I haven't loaded the source code yet. I also wonder about porting (not myself) OpenWRT to it (it does not do wireless but it does ADSL). Someof the ADSL modems are listed as work in progress (actually the 300T is listed somewhere).