Just having this thread has helped focus me more.
The Dervish allows you to take 10 on Tumble at any time. Unfortunately, I have no interest in being a Dervish.
The Tattooed Monk has the Monkey Tattoo which gives +1 on Tumble for every tattoo you have. Without using "this includes normal tattoos" cheese, this would be a slow and suboptimal way to get a bonus...
On the other hand, I just popped the MIC and it does have some stuff. Belt of Ultimate Athleticism is awesome, although the belt slot is tough...
Skin of Nimbleness is also very cool.
Thanks for the suggestion.