Hidden Gem,
William F. Bell is better known as Billy Bell, Jr. His father, William P. Bell collaborated with George Thomas, constructing (I think) LA, Riviera, Stanford and Ojai. Some give Billy Bell, Sr. much of the credit for the great original bunkers at these courses. He also is designed on his own (Brookside). (Billy Bell, Sr. is discussed in the Geoff Shackelford Interview, Part 2. )
Billy Bell, Jr. designed a number of courses in Southern California, including Sandpiper, Industry Hills, and Torrey Pines (with his father?). I am sure that Tommy Naccarato or one of the Shackelfords can tell you much more about the Bells if you are interested.
As for El Cab, it is known around L.A. as a difficult course, but is not quite as well respected as the big three-- some put in on the same tier as Wilshire. I have only played it once and enjoyed it. Generally good green complexes with tight, demanding greenside bunkering. A few really silly greenside concrete ponds. Many of the fairways are lined with soldier rows of mature trees to seperate adjacent fairways. Unfortunately, the trees take many interesting undulations and angles out of play.
Also, the course seems to have bought into the notion that tall rough and narrow fairways make for interesting golf. The course does offer some strategy (as you note), but I think it would be be more interesting if some trees were cut and some roughs were mowed to give the golfer some more options. I am sure that most of their membership disagrees with me.
While I wouldn't plan a vacation around playing El Cab. I would certainly drive over Sepulveda Pass into the Valley to play it, even in the summer.