UO's economy is a very interesting puzzle and there is no silver bullet that can solve all of the perceived issues with it.
I believe that the value of gold in UO is actually kept artificially high right now, simply because moving large quantities of it around is so difficult. Massive amounts of it are stored on player-run vendors and in chests full of checks. I'd bet that if all that cash were to suddenly become fully liquid, we'd see an absolutely staggering level of inflation overnight.
Now, I don't necessarily think that is a bad thing. But, a great deal of wealth in UO is stored up in non-currency form. If gold were to suddenly inflate or deflate by an order of magnitude or more, a bunch of people will take big baths either way.
I believe UO still has the problem of insufficient gold sinks. I also think that due to the extreme amount of gold in the game already, we must find a drain big enough to remove a large portion of those enormous reserves. The problem is, with gold's value being artificially high, it will be difficult to create such a drain because its cost will be seen as obscenely high. Plus, if large drains like that actually worked and started to bring the value of gold in line with reality, then the prices of big-ticket gold sinks would become truly outrageous.
Having the system dynamically adjust the price of big gold sinks could work, but I do believe that the portion of the playerbase holding most of the gold would collude, either explicitly or implicitly, to game them into ineffectiveness. Basically, if you have a lot of gold, then you can put upward pressure on the value of that gold simply by keeping it out of circulation.
As always, this is a subject that the team is aware of and we're always talking about different things to do. Of course, any game-changers related directly to UO's core economics must be approached with extreme caution...
