Why Polo and Kraken? Are you targeting ETH investors?
The major inconvenience with XRP is that you can`t keep your coins on your machine. Thus it`s not easy to convince investors that they keep their coins on exchange platforms for months.
Here is a post I located regarding a wallet
http://www.xrpchat.com/topic/665-ripple-wallet/#comment-5173I know they're out there, you may just need to do some research.
Are u kidding? The coder states:
I'm a novice coder, the wallet is in alpha stage and full of some quick dirty codes.... So, use with caution.... Do you think anyone will trust that wallet?
When Ripple company hosted wallets it was relatively secure to store coins with them, but from April they sill no more provide wallets on their official website. So at this stage the most secure way is to store coins on your own devices that seems impossible at this stage.