japan may make one. The whole point of the super-strut system was to improve cornering over the base model. Since it's not a factory feature (or option) on USA-Spec celicas, not many people have the super-strut package around here. To most of us, SS suspension would be considered an upgrade.
Japan, since Super Strut is available on the GTS standard, most of the JDM coilover setups for the GTS should work with the super strut package. Brash-boy and Tien would be the other good bets to check out.
Tien isn't cheap, around $1000 USD
Remember, when searching for JDM parts, use the chassis code: ZZT231 (This is equivalent to euro-spec GTS)