Experimental idea for binding to views that don't exist yet in viewDidLoad.

Observables.swift

//
//  Observables.swift
//
//  Created by Daniel Tartaglia on 8/13/18.
//  Copyright © 2018 Daniel Tartaglia. MIT License.
//

extension ObservableType {
    func bind(to observables: Observables<String, E>, withKey key: String) -> Disposable {
        return observables.insert(key: key, value: self)
    }
}

class Observables<K, T> where K: Hashable {

    func insert<O: ObservableType>(key: K, value: O) -> Disposable where O.E == T {
        ensureSubject(for: key)
        return value.bind(to: subjects[key]!)
    }

    subscript (_ key: K) -> Observable<T> {
        ensureSubject(for: key)
        return subjects[key]!.asObservable()
    }

    private var subjects: [K: PublishSubject<T>] = [:]
    private let bag = DisposeBag()

    private func ensureSubject(for key: K) {
        if subjects[key] == nil {
            subjects[key] = PublishSubject<T>()
        }
    }
}