As far as the organ sound goes, I think it depends on what is important to you and what you already have. I’m not sure if you meant that you want the Rhodes and Hammond sounds to be in the same keyboard.
The Native Instruments B4 would be a good choice if you have a computer and if you don’t care about portability. You’d probably also want some kind of MIDI controller keyboard unless you’re planning on step editing the notes into a sequencer or something. The B4 sounds great and is relatively cheap. I think it costs around $180 (the Plus version is around $230). There is a demo version that you can try out. It also has a leslie effect which is decent.
Personally, my choice would be the Korg CX-3. It is much more expensive at around $1800 or so. But this is a good choice if the playability and keyboard are important to you. The keyboard has an authentic feel to it. The trigger point is very shallow like a real Hammond and it lets you do some of the more percussive things. The keys are rounded to let you do smears better. To me, playing a Hammond organ sound on a synth keyboard or a piano-type controller isn’t as good. The CX-3 also has real drawbars, a good leslie effect, and it’s portable. The sound is one of the best and most authentic.
If you want something in between, consider something by Voce like the V5. This is just a module, but it has real drawbars. I think the V5 got picked for most authentic B3 sound by Keyboard magazine. I don’t think they have a leslie effect, so you’d have to get an extra box for that if you want it. The V5 cost about $700. If you still need something separate and portable like a module, but the V5 cost too much, there is also the Voce Micro B II for $429.
I’ve never heard any Voce product, so I don’t know how they compare to the other stuff. I’m just going by what I’ve read. I have played
the Korg CX-3 and the NI B4. They both sound great and it’s hard to pick one over the other on sound alone because I didn’t play them at the same time.