It looks like Realm has it's own ORM. Given that, it might make more sense if you want to use it to implement it as a Rhodes native extension. It wouldn't make much sense to put Rhom ORM over something that already has an ORM.
I don't find SQLite limiting. In fact, quite the opposite. I make extensive use of SQLite views and triggers. (While there is nothing in the Rhodes docs about it, all SQLite features are available.) I actually don't often use the Rhom ORM, instead I use SQL expressions. I don't find performance lacking at all.
I am very skeptical about ALL "spooky database action at a distance" implementations. (I'm afraid including RhoConnect.) Recent exposure to Parse (a failed effort on the part of Facebook that has left thousands - well, 500,000 if you beleive the hype from the past...) of app projects scrambling for the exits) reinforces that skepticism.