Developing a read later client

Hi there,
Like many Kobo owners I was disappointed (though not surprised) at Mozilla's announcement. Unlike many, I'm an experienced mobile developer (though new to Kobo development). I'm wondering how feasible it would be to create an open source read later (to access Instapaper, Wallabag, etc) client.

Specifically, would cloning KOReader be a good place to start? Seems like it already has much of the tooling and functionality that I'd need. Would be an added bonus if I'm able to maintain cross-platform compatibility. Are there existing clones, or simpler projects out there that might be a better starting point and/or way to begin learning Kobo development?

If others are interested in this I'd welcome collaboration.

Thanks in advance.