As I said in my earlier post, Samba4 is still in alpha. If you read the link that I posted above you will see that whilst Samba4 has some very cool features it is still unstable (hence the alpha tag).
I think that considering it is not easily available for 8.04 (the basis of TKL) then we will not see it available and/or supplied by TKL until they release appliances based on Ubuntu 10.04 (due for release end April 2010 - Ubuntu that is not TKL - although they should follow a few weeks after I would expect).
I reckon the guys are too busy working on the new appliances to offer something like this that will probably cause them more headaches bug fixing and dealing with the inherrant stability issues of alpha software.
But like I said in my previous post, that doesn't mean you can't play with it if you want to. It just means that you will either need to compile it from source yourself or find someone who has and is willing to share. I guess anopther option is try to replicate the functionality of the TKL Fileserver using a later version of Ubuntu Server, which may well also be a steep learning curve.
So in a nutshell, here are your options:
More information about text formats