This is interesting. Just found this on "Doug's Scripts", which is only usable on macs:
Lossless to AAC Workflow v2.1
Two scripts assist with importing/managing Apple Lossless audio files and sending converted AAC copies to a mounted iPod set to "manually manage songs and videos".
Lossless to AAC Workflow (CD->iPod):
Imports each enabled CD track as an Apple Lossless file
Makes a converted AAC copy of each imported Lossless file
Adds the AAC file to iPod, deleting the original AAC from iTunes.
Lossless to AAC Workflow (iTunes->iPod):
Makes a converted AAC copy of each Lossless track selected in iTunes
Adds the AAC file to iPod, deleting the original AAC from iTunes.
In this way you can keep archived Lossless files on your hard drive, and manageable AAC files on your iPod.
Lossless to AAC Workflow v2.1
Two scripts assist with importing/managing Apple Lossless audio files and sending converted AAC copies to a mounted iPod set to "manually manage songs and videos".
Lossless to AAC Workflow (CD->iPod):
Imports each enabled CD track as an Apple Lossless file
Makes a converted AAC copy of each imported Lossless file
Adds the AAC file to iPod, deleting the original AAC from iTunes.
Lossless to AAC Workflow (iTunes->iPod):
Makes a converted AAC copy of each Lossless track selected in iTunes
Adds the AAC file to iPod, deleting the original AAC from iTunes.
In this way you can keep archived Lossless files on your hard drive, and manageable AAC files on your iPod.