Based on Delfim's stuff and my previous tinkering here's an AppleScript that stores e-mails under a Personal/Year/Quarter tree.
(Despite having several accounts configured, I archive everything under my Home account.)
It is designed to be activated from a Mail.app rule (or via Mail Act-On):
using terms from application "Mail"
on perform mail action with messages theMessages for rule theRule
tell application "Mail"
repeat with thisMessage in theMessages
set msgDate to date received of thisMessage
set msgMonth to month of msgDate as integer
set msgYear to year of msgDate as integer
set msgQuarter to ((round ((msgMonth - 1) / 3) rounding down) + 1)
set msgAccount to name of account of mailbox of thisMessage
set msgMailbox to name of mailbox of thisMessage
set mboxName to "Personal/" & msgYear & "/Q" & msgQuarter
tell account "Home"
try
set mbox to mailbox named mboxName
get name of mbox
on error
make new mailbox with properties {name:mboxName}
set mbox to mailbox named mboxName
end try
move thisMessage to mbox
end tell
end repeat
end tell
end perform mail action with messages
end using terms from