Selecting "Audiobooks" closes the iPod application since upgrading to 2.1

Question

Since I upgraded to the 2.1 version of software for my iPhone 3G, I have been unable to use it to listen to Audiobooks. Each time I select "Audiobooks" in the iPod menu it freezes for a couple of seconds and then pops me back out into the home screen. (See partial crash log below)
I have tried restoring the phone, but that didn't fix the problem.
Has anyone else experienced this issue and have a suggested fix or workaround.
Thanks
Process: MobileMusicPlayer [298]
Path: /Applications/MobileMusicPlayer.app/MobileMusicPlayer
Identifier: MobileMusicPlayer
Version: ??? (???)
Code Type: ARM (Native)
Parent Process: launchd [1]
Date/Time: 2008-09-13 21:26:54.282 -0700
OS Version: iPhone OS 2.1 (5F136)
Report Version: 103
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x00000000, 0x00000000
Crashed Thread: 0

Answer 1

After a couple hours of testing last night, syncing and re-syncing, and crashing and crashing and crashing, I can add some specific facts, and provide details for a couple work-arounds (at the end).
1. The problem occurs when you try to click to the Audiobooks tab/panel of the iPod application. If I quit the iPod application while on (say) podcasts, I can re-launch the iPod application, and do anything but go to the Audiobooks tab, without causing a crash. (This makes an audiobooks playlist workaround a reasonable strategy while waiting for Apple to fix this defect.)
2. If I quit the iPod application while in the Audiobooks section, and then sync over audiobooks that trigger the problem, then the entire iPod application becomes inaccessible. That is, you can try to launch it, but it hangs, and then goes back to the desktop. The only way to get your iPod back is to re-sync and reduce the number of non-Audible tracks. If you're not at your computer, you're screwed.
3. Only non-Audible books seem to trigger the problem. I am able to sync 50+ audiobooks from Audible.com (all Type 4) and it seems to cause no problems. No specific or quantity of Audible.com Type 4 audiobooks seem to trigger crashes. (I imagine that this is somehow related to the Audible titles being relegated to the Audible ghetto, below the regular audiobooks list, instead of mixed in with the rest of my audiobooks. Which seems to me to be a dumb UI decision; why would I care where they were from? I just want my audiobooks in one place. But that's another rant.)
4. I currently have 18 non-Audible audiobook titles, consisting of 23 separate tracks (a couple books are multiple tracks, but only show up as one entry in the Audiobooks list on the iPhone), synced to my iPod, and I can use it normally. Adding one more track, and the Audiobooks section starts crashing. With another combination of audiobooks, I got it to 18 non-Audible entries in the list, but only 20 tracks. So it appears that the defect is triggered by having more than 18 entries in the Audiobooks list.
5. It doesn't matter what title I add, only that I hit the limit. I must have crashed the iPod application 100 times last night, testing my way through a playlist of 105 items...
6. All but one of the non-Audible tracks are AAC files (.m4a) that I have switched the file extension on, to .m4b, so they would show up in the Audiobooks section of iTunes and my iPhone (prior to iTunes 8, the .m4b extension was the only way to achieve that). The other track is a plain AAC (.m4a).
I hope this is useful in devising work-arounds. In particular, two possibilities seem like reasonable ways to cope while we wait for Apple to track the defect down:
1. Limit the number of (non-Audible) audiobooks synced to your iPhone / iPod Touch. You might find the following article helpful in that regard: Managing audiobooks on a small-capacity iPod -- http://aldoblog.com/audiobooks/itunes/managing-audiobooks-on-a-small-capacity-ip od/
I may receive some form of compensation, financial or otherwise, from my recommendation or link.
<Edited by Moderator>
In particular, the tips about creating smart playlists that you sync to the device, with filtering based on type and limits based on number of tracks, would seem to be strategies that will make it simpler to deal with this problem.
2. Create a single big playlist with all your audiobooks (maybe a smart playlist based on Genre starts with "Audiobook"), and use that to get to your audiobooks, rather than the Audiobooks application.