Hi, well I don´t really know that, I´m using QT, because it doesn´t give any problems really

Probably losless AVI is as good or better, but honestly I have not try AVIs.
The fact that is 10 bit or 8 for me at that point is a bit useless, as where I take advantage of the amount of info store in the raw files is in Adobe Camera Raw, then once I ´ve done all the adjustments for colour and lighting in AE I export it to Premiere to edit the shots and render out to something that Vimeo can swallow.

All this is just for the tests, as been able to adjust the footage with ACR is just pretty new

With standard (no raw) footage usually I would do the opposite, import into premiere first, edit and then colour grade it, but since only AE allow me to import dng I start from there instead of premiere.
I´ve just done a quick search these could help you with the amount of colours stored in the files regarding if 8bits, 10bits, 12bits, etc...
http://www.techhive.com/article/171223/10_bit_color.html