1/5th planning. Redcat Rampage & what ESC/motor/LiPo combo?

[Marvin]

So I'm looking at building a 5th Scale for the 1st time. It's going to be built for some friendly racing with some Losi 5ives, Bajas and the like, so I'd like 4WD. This drew me towards the Redcat Rampage XBE (or Maverick in the UK). I'm assuming that the stock electrics are not great, so I'm more interested in the car itself. Would it be better to go down this route, or go for something like an MCD (sport no engine versions are about £600 vs <£500 for the Maverick)? Don't really want to go the 5ive route due to the weight and the non-rolling nature of the chassis (don't need all the engine and bits...).

As for electrics, I'd like to go 10 or 12S for efficiency reasons, but this moves me out of "normal" ESC territory. What's the stuff to buy at this voltage? What motor size would be required? I'm happy to spend a bit of cash to ensure reliability, though am not loaded. Castle's stuff has traditionally been around the correct price point for me. Would a Pheonix ICE HV2 be appropriate in conjunction with mechanical brakes?

Or is 8S really enough in combination with the Castle XL2 & 2028? Is the XL2 past the initial "it's gonna blow" phase and generally a safe choice?

As for batteries, I'm aiming for 40-50 minute run times on track (though not driving that hard), what sort of capacity would be required? 8S 5000mAh enough? Or 10S 5000mAh with appropriate KV/gearing? Or more?