Given that the back deck on a TR7 is pretty flat I would think any number of generic rear wings would work, and most have built in brake lights. Some even have LED rear lights, although I think that might look a little out of place on a TR. You shouldn't need anything TR7 specific, just measure the width of the rear deck and start looking for wings that aren't wider than the max width. Unless you want to look like one of those ricer kids and have a huge 747 airbrake on the back of your car.
Try some local customizing shops, they usually have catalogs full of those things. Even body shops sometimes can order custom body pieces. Personally I think a rear lip spoiler, or ducktail as they are sometimes called, would look awesome on a TR7 instead of a wing, but to each his own.