The requirement to run a DM (decentralized Masternode) will start at 1 SPR if I understood Mr.Spread correctly.
Because it is not necessary to set a minimum deposit price, much like it is not necessary to set a maximum deposit price.It will be decided by the free market, much like bitcoin's difficulty is decided by the free market.
ONLY a maximum number of DMs must be defined.
Now let me ask you, since you say only the richest SPR holders will be able to afford DMs:
Who makes it EASIER to run a DM/MN?
Spreadcoin with a dynamic Deposit Requirement starting at 1 SPR, (letting the free market decide)
or Darkcoin who has a FIX Deposit Requirement of 1000 DRK? (Cutting out 99% of all investors from the start!!!)

Good luck with your 1000 1-SPR Masternodes costing you $5000/month and earning you nothing because everyone else is going to be bidding the requirement up to the max.