I would give my i-teeth to lay my hands on a 1/32 Phantom Mustang! Good luck finding one.
If you check on the Great Models website, you should be able to find the Hasegawa 1/70 scale P-51D Mustang Skeleton Classic (use their datbase search feature). A smaller version, but maybe it will satisfy your hankering for a cut-away Mustang.
http://www.greatmodels.com