UKC

Ive read previously that shimano and magura brake levers / calipers are interchangeable and people do this for various reasons.

Does anyone happen to know if any shimano 4 pot lever would work with magura MT5 caliper?

I'm not sure what you mean by 4 pot lever, brake levers are brake levers that push brake fluid and will work with any caliper (2 pot or 4 pot) that runs the same type. Magura and Shimano both run mineral oil so you should be able to use any lever with any caliper. Most people seem to use a high end Shimano lever to increase power as these have a servowave cam with various calipers (Magura, TRP, etc), gives more of an on off lever feel though and can reduce modulation which you may or may not like. 

That's pretty much what I was hoping to hear. I thought 4 pot (piston) would need more fluid movement than 2, but thats just a guess. 

Yes it works and bloody well- I have XT levers (Though i think SLX Deore etc would work just fine) and MT5 calipers. Using Magura hoses and Shimano fittings/olives to ensure a good seal at the lever. I use Magura brake fluid as it's what the calipers are designed for and obv where the brakes will be getting hot. Probably stating the obvious but use Magura rotors, they're thicker and part of the reason (I think) that they shed heat so well. 

Overall a great, cost effective fix for the trashy, leaky,  PITA to bleed levers Magura seem to like making- I'm assuming this is why you're asking this ;p

😉 Spot on reasoning.

I've just ordered a deore lever, will be using a2z brake vodka as usual thanks both.