I think RAM should be equivalent to coffee or other perishable commodities markets. The producer (i.e. block producers) sell "1MB RAM futures" contracts with 1month, 3months and 12months expiries, and offers them on a regular bid/ask market. Those expiry dates are the day of "delivery", i.e. you get the RAM from then on and can't sell it on the market. So the ultimate consumer of the RAM (i.e. the dApp developers) can purchase RAM futures a little bit (or a lot) ahead of time. This puts enormous downward pressure to the true value of RAM for dApps, towards the end of the contract, and it means that there is serious limits to how high the market dare to go in the interim (greater fools).
Possibly add a "buy back"-guarantee that the block producers issue initially with the contract, at 50% of the contract sales price.
The tricky bit is to find the "initial contract price", since there is truly no competition between the block producers. Perhaps a closed bid procedure, and the median value is the price, but only the lowest 1/3 of block producers will be given the sales reward.
Once you have the futures market in place, one could also introduce an OTC Call Options market, mainly to lower risk for dApps developers. For those who don't know Call Options; It is a contract where the Developer buys the right, but not obligation, to purchase RAM at a "strike price" at a "expiry date", and for that the Developer pays a premium up front.
This provides "interest" for speculators and lowers risk and cost for dapps developers.
Such call options market should also be bid/ask exchange traded.
Some staking would be needed for those who sell the contracts, and should probably feature "lock in profit", that locks down the RAM (in possession) to be available for the sale (should it materialize) and the staked token then be released for issuance of new options contracts.
Author: Niclas Hedhman, CTO at EOS Germany