I too have recently had this thought. Bvt's reply is the best I have seen in response. I have seen the Crye Covers, but dont know how popular they are in country though. I've not seen any in the AOs I've been in personally.
The tan thing, your exactly right. Guys dont have a reason for it, just that some SF guy was wearing it (nevermind thats what they are issued). I think MC would be ideal in 9/10 circumstances and MARPATs certainly got fewer disadvantages than ACU pattern does. The only reason I went Tan on my gear is because its commonly accepted in my unit and MC is not issued out or accepted in most circles.