Thanks for the info Quindor.
Looking at posts 201-219 in the thread at HardForum, it seems like at least some newly purchased Western Digital desktop drives still support WDTLER.
Unfortunately Smartmontools doesn't support Intel ICH RAID at this point. Here's the list of supported controllers.
My disks support WDTLER so this way of setting the timeout isn't really needed but I tried it anyway (in AHCI mode):
Brand Type Type2 Size RPM Revision Firmware Available Default Reboot Powercycle
WD WD10EADS-00L5B1 Caviar Green 1.0TB 5400 ? 01.01A01 Yes Disabled Stay Lost