We would really want to implement this in a new mobile HTML5 app for iphone/android devices first.
Current work in progress for the offline HTML5 hybrid app, please try it: https://checkvist.com/auth/mobile
We also have a separate feature pool for it:
Hey guys, native app is not only the biggest feature we need here. But its huge marketing oppotunity for you. It could add thousands of users to your userbase.
And there are alot of monetization possibilities by the way. :)
I'm really surprised that there is still no native+offline versions for mobile devices.
You have amazing product! And absence of that feature is the only thing thats stops me from using it every day and from buying paid version immidiately.
If i were you i would find a fastest way to implement that (investiors/open sourcing/crowdfunding/...).