I've encountered the same problem; I want to make some custom fields translatable.
I'm working on a web project using SS and today when I wanted to implement custome field functionality, It gave me 'can not run query' error and referred to non existing column in SiteTree table named OriginalLangID.
As I should deliver my project next week, I would appreciate to access the patch early. I was thinking about extending $db static variable in SiteTree class and add all of custom fields and then selectively disable them in each page type I've created. Although it is non-efficient but quick fix that I think functional.
I've not tried daily builds yet, Do u think if I upgrade my local copy with latest daily build files, my problem is solved?

I tried to do the same but was not lucky. My site has just several pages with the same sidebar content in custom areas. So, I did a trick creating separate pages with the needed content for custom blocks and called that content from those blocks in the template.
This is not a perfect solution, but I'll wait until the patch is released and custom fields that we create for the cms become fully translatable.

Is there any news on the translations of custom fields ?
Anyone had any succes with the i8n functionality in a production environment ?

no news yet, make sure to follow the progress of these tickets:
http://open.silverstripe.com/ticket/2202
http://open.silverstripe.com/ticket/2165

Thanks Ingo...

Just to be sure ; there is no (quick,dirty) way to use the I8N functionality for pages that have custom fields , correct ?

not that i'm aware of, sorry mate

so is where any avalaible branch with this bug fixed?

Any update on this? I've stumbled across the exact same problem and I'm in desperate need to get a fix for this...

I'm running SilverStripe 2.2.2 and the problem is still the same.