For reasons I do not begin to understand, the combination of iTunes 7.5 and the 1.1.2 iPhone once again allow you to add custom ringtones without fussing with property lists and special software. Take any m4a file, thirty-seconds or less (although some report success with tracks up to 40 seconds), rename it to m4r and double-click to add it to iTunes. The file appears in your ringtones and can be synched--I tested this out myself--to your iPhone.
So has Apple relented? Or is this a momentary lapse of oversight? Only time will tell.
Thanks to Dave P