Its really not all that hard to do safely for both parties... even in the amount of 800mil+. We have an unreal amount of items in game that are worth over 10mil. Most transfer tokens sell for around 20 mil. Lets say you agree to pay 800 mil for a castle. You can not put 800 mil into a trade window. But you CAN put 40 Transfer Tokens in a trade window. The recipient can then sell those transfer tokens for 20 mil a piece and boom... a clean 800 mil deal.
Now it will be a little more work trying to establish a fair market price for the items used... but I think the extra work is well worth the safety to both parties. When I bought my castle, I payed something like 75mil, 4 transfer tokens, 4 Advanced Char tokens, An event robe, an Orny, and Inquis, and a couple of other things that were worth a good amount. The total value was around 350 mil. When He had the items and I had the castle, I then bought each item back for the agreed upon price. Now, if I had tried to screw him and took off after I had the castle, then all he had to do was sell the valuable items to other players and he would still have all his money. If he had tried to scam me and taken off with my items once we had traded, well I still had the castle and all that gold I could just go to luna and buy pretty much everything back. But it was easier for both of us to hold up our end of the bargain then for either of us to try and scam the other. And it was all done in one clean trade window with no risk, no broker fees, and no hassle.
Again, it will take a little extra time to agree on what the items used are worth. But you will not have to worry about getting scammed, and that is priceless.
