Whats the reason why you want to have a wallet that has customizable fee with more than 0.005 btc, even 0.005 is already high enough for a transaction fee. That's not necessary to have huge TX fee, you only need to base your fee with this site bitcoinfees.21.co(I know you knew it already) but even you have to send huge amount of btc just follow that site and use viabtc accelarator to push your transaction fee.
If you having problem fee i think you need to stop on using bitcoin on your transaction or just find a suitable wallet for you. Because fee helps the developer of bitcoin to develop and upgrade bitcoin quality in transacting. I suggest you to use an application wallet not an offline because online wallet is more suitable on transaction. Besides almost of country i reachable via internet. So in holding and transaction of your bitcoin will not be so hard for you.