i wouldnt really bother with the shields off kresh for elemental shaman maybe the seedcloud buckler off of verdan the everliving or the arctic buckler from the bfd quest . i know the arctic buckler is considered the best caster shaman shield in the 19 twink bracket for what its worth

although with lack of any better caster shields for a lot of levels you may want to look into staves or 1 hander/offhand frill options. staves may be your best bet.