3kg and 10l sacks are pretty extreme, even on the Elite class. I got everything in a 15l sack for a couple of solo MMs, but it resembled one of those "snakes in a can" tricks when I opened it at mid-camp, and I expended a significant amout of energy on the morning of day 2 pummeling everything back in. I now use a 20l sack which weighs virtually the same and makes life easier.
Solid fuel blocks is a great shout. Much lighter and smaller (and cheaper) than gas and stove, and it's not like you don't have a few extra minutes in camp to wait for your water to boil. Spending a bomb on a light tent makes a massive difference. You can get a Terra Nova sub 700g job for maybe £300. Lightweight sleeping bag makes a big difference too. Beyond that it's how light your clothing and food are, and how much of each you need to take to survive (or be comfortable, but I'm guessing you're a survival kinda guy).
Another tip from my previous OMM partner is rather than taking dry socks for day 2, simply cook day 1's socks in the morning. It looks and smells a little odd, but he tells me they sure are toasty. I tend to go with wet, cold socks.
What course you doing? Hopefully see you there.

