My son Tom and I just purchased Standard Cirrus S/N 206, N4024.  We are the 6th owners, near as we can tell, and it came equipped with a hydraulic disk brake, operated by the spoiler control linkage.  

Based on the records, this conversion was done by the original owner in about 1977 (based on the date of the form 337.  The ship was re certified as "experimental" at that time.  In 1981, a supplimental, standard airworthiness certificate, SG535GL was issued.  

The brake system was produced by Jensen Aircraft. The drawings indicate that it was designed specifically for the Standard Cirrus in 1976.  Shure hope they are in business if I ever need parts.

Gehrlein Products name appears on the 337 in the Conformity section.  I don't know if they were the supplier or the installer.  

Jensen's weight calculations show a net increase of 3.3 Lbs for the conversion.  Anyone who wants info on this can contact me at ctstoltz@yahoo.com