Well, let's see.. Well, vouches helped me a lot in trading and people that say: "Vouches mean nothing!" - you are wrong. They do mean that the dude did trades, that they were successful and that yours could be also successful. Of course, when talking about those silly vouches for no trading (well, I've had few too, those were for giving away free names, that I thought were cool), well those vouches shouldn't mean nothing as there's no entrusting with something at all. You just give away that you have too much.
Suggestion: Only a man with 200+ posts and 20+ vouches can vouch. There should be some kind of vouch system that would have their own moderators, some kind of new section, like having some moderators see up the vouches, well, like looking up at IPs maybe some kind of proof, MSN log with saying sythe names+msn's+runescape acc names and in game pic of receiving/giving away payments.
Now imagine: I'm a leecher, I'm new in Sythe and I want to trade, I see the new system of vouching and I make some kind of Application to it, I'm finding members with who I would like to do trades and then after we did it we vouch each others, after you get 20 vouches from so called "Vouchers" (dudes that have the ability to vouch) and get 200 posts(well that could be also looked through those moderators if those posts were not just random spam and were with some kind of idea in it) then you become a "Voucher", you can vouch others too.
Well that'd be my idea.. Of course, the vouch count and the post count could be changed, but in my opinion, it's enough. By post count, I mean that after they got that 200 posts, then they would know something about Sythe, it's rules and everything. ^_^