Locking coins from being sold

I'm hoping to get some technical advice with this post as well as opinions on how this service will be received.
I'm trying to build a blockchain service on a new public blockchain / coin. The basic premise of the project is building an altcoin to support a commercial service,that verifies certain real world transactions by storing the transaction as a blockchain transaction.

I've considered using a private clockchain for the service, but ideally it should be public. Now releasing this as a coin means I will need miners to support the coin. For the service to work, I will need to own a large amount of coins to use in transactions. This means premining coins. This won't be a scamcoin where these coins will be dumped into the market for monetary gains. So to protect the investment of prospective miners of the coin, I need to find a way to lock the premined coins, so cannot be traded into the market. If I can guarantee that the premined coins never enter the market, the value of the coin can increase without fear of a market crash. If I can remove the premined coins from free circulation it will mean that even if my commercial venture fails, the rest of the mined currency will carry on and nobody should lose the work they put into mining and trading the coin.

So far I have 2 possible ideas:

1. Make it so that these coins can only be traded between 2 predefined wallets. Although this option will limit my development of my application a bit.
2. Make a public statement and a guarantee within my t'&c's that I will never dump coins into the market. I trust myself on this, but I don't expect anyone else to blindly do so.

I'm looking for a third option.

The coin I will be releasing will of course come with all the basic tools and will be a CPU mined coin. On providing value for the public coin side of it, I will eventually build multiple open source tools for developers to use and make the coin really usable as a cryptocurreny with a working ecosystem of apps built on top of it.

So any opinions or advice will be appreciated.