The Chazan

In Frankfurt there was a special hat and special robe for the chazzan and for the Rov.
The minhag was started at the time by Rav Hirsch for reasons he saw appropriate, but Rav Hirsch's Rov - the Oruch Laner held there is a problem of Chukas Hagoyim with this minhag, see:
תשובות הערוך לנר החדשות (בנין ציון ח"ג) סימן ב
The Oruch Laner claims that the only special clothing for the chazzan is the Tallis, which is worn in every תפלה, (including Arvis).
For this reason, every Kehilla follows the Psak of their Rov regarding this issue. In KAYJ this minhag is not practiced.
FRBSH

I asked R' Yisroel Strauss about the minhag in KAJ and this was his answer:
"The kaepchen (special hat on the head) is an old minhag, but with the black robe for Rabbonim and chazzonim there may be a problem of Chukos Hagoi. They say that Rav Shlomo Zalman Breur said – after me no one will wear this robe, and he was right. Rav Horowitz didn't wear the robe any more. “
Michael

MPerlman wrote: Is wearing a Homburg hat also a MA?

The Jewish clothing changed throughout the generations. The Chassidim considered the fur hat and the silk clothes on Shabbos as Jewish clothes, since this was the clothing of the 18th century. In the 19th century the top hat was used (not only in Germany, also in Eastern Europe, there are pictures of the Lithuanian Gedolim with a top hat), and the Homburg hat was used just before the 20th century.
It is interesting to note that Harav Moshe Mordechai Epstein, the Rosh Yeshivah of Slobodka and Chevron, has one picture in a fur hat (a Spodik), and another picture with a top hat. On Shabbos he wore one, and the latter on the weekdays.

FRBSH

Steven wrote: Does anyone know where a Chazzan "Kaepchen" can be obtained?

We don't use a Kaepchen in KAYJ (unfortunately), so we don't have data on this issue. I'm sure people from WH would have more data about this.

Michael

Steven wrote: Does anyone know where a Chazzan "Kaepchen" can be obtained?

Kaepchen's can be obtained from Yehonatan Neuman (Kehillas Austreich Modi'in Illit) for 30 NIS + shipping (credit cards accepted).

His phone numbers are : 0527167567, 089218423.

I was pointed out that this isn't the same Kaepchen which was used in FFAM and is used in KAJ Washington Heights. You can see in the picture attached the Kaepchen used by Chazzan Frankel on Shabbossos in KAJ WH.

Attached are two photos of the Chazzan's Kaepchen. The photos were taken by R' Ezra Lasdun, the Chazzan of KAJ WH (Breuer's). The Big Kaepchen is for Shabbos and the smaller one next to it is for weekdays. (The Shabbos Kaepchen is stiffer than the weekday one).