Let me begin by saying I have very little experience in this, but it seems that Losi 8ight and Associated RC8 are both very good top-end choices.
You can get the RCPD kit
for them (needed to mount the motor and batteries), and the rest you already have/mentioned.
I'm not too sure about Ofna's buggies, but it seems they are also quite decent but much cheaper alternatives.
P.S. Personally, I've got a new Losi 8ight roller sitting that I want to convert, but due to the whole Monster Mamba fiasco I'm waiting a little while longer before I go through with the conversion.