The idea is inspired by revcoin's topic
http://forum.bitcoin.org/index.php?topic=19278.0To prevent deflationary spiral that may come some day, I have a very simple suggestion: all the miners and mining pools make an agreement that transaction fee should be a function of activity(or "age") of payer's address/account, which can easily checked by tracing back it's information in old blocks. Old account will spend more transaction fee to make the transaction confirmed, unless the payer build a powerful mining rig and successfully create a block to include that transaction.
For those account with huge amount of bitcoins, if the owner want to spend them in some day that each bitcoin can exchange for 10000$, he/she may only be able to trans 1% of them, and the rest 99% will be charged as transaction fee. He or She will still be a rich person, but bitcoin will not make any one a billionaire by simply hold a large amount of bitcoin for several years.
I think the idea is feasible: miners can earn more by this 'rule', and daily users of bitcoin will not worry about the bitcoin they spent will have severalfold purchasing power after one year and grudge to use them.
With this "rule", bitcoin will become a "currency" rather than "digital gold".