DX7 would be a nice choice! That's what I would have suggested, but I am not familiar with the other boards you mentioned.
If you're going for an authentic look, by all means, go with a DX7. If you're not partial to the way your setup looks, you could always try
the TX7, which is the rackmount version of the DX7, which you can use with any midi controller. I have one myself, and picked it up on eBay for only a bit more than $50. There is also
the TX816, (I believe that's the number.) It's the multi-rack mount version of the DX7. It gives you more layering and split capabilites you just can't get with the TX7, as well as more space for patches.
You could always get a nice vintage controller to go with it, though that would cost you more. One such nice one would be the Yamaha KX88. It's one beast of a controller, but it's supposed to have amazingly realistic piano action. I would pick one up if I could literally pick it up! (I want to say around 80-100lbs, not certain by any means. I just know it's heavy, and I wouldn't be able to lug that around a couple days a week by myself.)