Hmmm. If you had the launcher start up and it detected your settings, it should have created, even if it crashed, the .ini file. I'm pretty stumped on this one. Have you tried, by chance just basic wine and followed the directions on winehq.org? There is also another program (front end) for wine that is mentioned there that I have used before and it worked.
To change your bottle so that it's launched in a bottle: (This is done on linux and I'm assuming the mac version follows the game parameters.)
Go to your crossover directory or menu. Then go to "Manage Bottles"
Select your Fallout 3 bottle (whatever you named it), then click the "Control Panel" tab.
Select "Wine Configuration", then "Launch Selected Item"
A new window should open that is called "Wine Configuration". From there select the "Graphics" tab, then add a check to the box beside "Emulate a virtual desktop". You can change the desktop size right under the box you checked. I would recommend just leaving it as is to see if it will work.
Then click on "OK" and close the "Manage Bottles" window. And try to launch Fallout 3 again.
As an alternative to running the launcher, you can launch the game directly from "Run a Windows Command" under the crossover games directory/menu. Just choose "Run a Windows Command", then make sure your fallout 3 bottle is selected, and browse through the directories to find fallout3.exe. Don't just type in "fallout3.exe" as it will not work.
The directory layout should be something similar to
Program Files -> Steam -> Steamapps -> (your steam login name) -> common -> Fallout3 or Bethesda (not sure) -> fallout3.exe
I really really hope this works. If not, then you can create some debug logs from it, and file a bug report with it. However, I would submit a bug report before making the debug logs cause the fine people that will help you with this and let you know what logs they will need to help you.