Just a bit of research.

Are there any parts that used to be avaliable in white metal people would like to see produced again?

What immediately comes to mind is anything in the Beaver range, particularly the coach underframe fittings such as dynamos, battery boxes etc

The EM2 bogie sideframes. I cannot remember who made them but they are very close to the D600 Warships and the LMS Twins. Knew I should have bought more when they were available!