dc42 (and others)
Lead / Tin solder is NOT illegal in the EU for "Fine Trace" boards. (I believe that people use .650 mm trace spacing for this standard.)
The problems with Tin Whiskers is serious enough that exertions are (routinely) granted for "fine trace" boards.
See here:
http://www.calce.umd.edu/lead-free/STMAKeyNote.pdf
Pg 19/29 for example.
See here as well:
Whoever brought up the dangers of lead: Spare us the lectures on the dangers of lead. People in engineering and design are well aware of the dangers.