alternate psql file locations

It's not a big thing, but I just found myself in a shared environment 
wanting to be able to set alternative locations for the psql startup 
file and history. I know there's the HISTFILE variable, but I can't 
easily set that automatically unless I can at least have my own .psqlrc. 
ISTM it should be a fairly simple thing to provide these, via 
environment variables. Is there general interest in such a thing?

cheers

andrew