Slightly shorter variant...

python -c $'
import portage, time
from itertools import chain, imap
target=long(time.strftime("%s",time.gmtime())) - 24*60*60
pdb=portage.portdb
for cpv in chain(*imap(pdb.cp_list, pdb.cp_all())):
	flagged=False
	try:	mtime, eclasses = pdb.aux_get(cpv,["_mtime_","INHERITED"])
	except SystemExit:	raise
	except:	continue
	if mtime >= target:	flagged=True
	else:
		try:
			for e in eclasses.split():
				if pdb.eclassdb.eclasses[e][1] >= target:
					flagged=True
					break
		except KeyError:	flagged=True
	if flagged:	print cpv
'

~brian