Linear makes the LT1716, inputs can go to 44 v regardless of supply, according to the datasheet. Looks like it costs a little more than the TI comparator. I cross-posted this to some other newsgroups in hopes of hearing of other high-side comparators. I didn't know about the TLV370x until I saw your post. That's a real micropower chip. Take a look at the graphs for output. You really don't want to put much of a load on it.
You also have the option of using a high-side op amp as a comparator, especially since you don't need nanosecond response times. FET op amps like the TL08x are very common and fairly cheap. You can even get them with nulling pins.