Hi,

Are there any books that describe clothing alterations for magicians?

Secret pockets and what not?

I do not have the book in front of me, but I believe that in Henning Nelms book, Magic and Showmanship: A Handbook for Conjurers, has some things in it, but it is for dove workers.
There is a book put out by Michael Ammar also that describes and teaches the use of a special pocket also.

Exept a book to make topit, you can find info on tunel on Steve Bedwell dvd.
On clothing alteration you have tunnel, topit, black art principle, magnet insertion, load pocket...
I think your stuff and routin will defined the alteration you need.
Check the Xavier mortimer penguin live.

DragonLore, I have an excellent clothes alteration source. I know this post is almost a year old, but if you are still searching.

You can find a great deceiving pocket holder idea to make large productions sleeveless on the Penguin Live Online Lecture - Kevin James DVD.

Brian Gillis used the idea on a commercial once to appear prunes. It's been a while since I have seen the video, but I believe the original concept came from Sylvester the Jester.

https://www.sylvesterthejester.com/

Good luck to everyone else reading this post looking for material on this subject.