I've searched quite a bit and have come up with little to nothing on the former estate of Glenn McCarthy - it sat where the Brentwood and 7575 Kirby condominiums currently are (northeast corner of Kirby and North Braeswood, right across from Jenkins' 2530 Underwood house). It was designed by Milton McGinty and completed by 1938. McCarthy bought the land from Rice Institute in 1935 and later sold it to Harold Farb in 1972. It was demolished some time between 1972 and 1977.
Other than some newspaper articles about its construction and a mention of it in the Anchorage Foundation's Braeswood: An Architectural History, there doesn't seem to be much else out there. Anyone have any information or memories?