The organs and EP's in those synths will be okay, but the pianos--ugh. It really was the next generation of synth that the pianos got even passable. Also, most of those units are keyboards, not modules.
Something like
a Roland JV-1080 or 2080 with an SR-JV piano expansion board would be a good choice that won't break the bank. There is also a "Keyboards of the 60's and 70's" SR-JV expansion board that has a lot of organs and EP's on it.
Emu had a 1/2 rack module called the "Proformance" that has pianos and I believe a few EP's. Likewise, Kurzweil had a small 1/2 rack module as well with a good piano.
The Kurzweil
PX 1000 has an excellent piano, as does later modules in the series like the PX Plus and PRO 1. The selection of EP's and organs in those modules is a bit limited though.
Really, your best bet might be to find a Roland 1080 and put the SR-JV piano expansion board in it.
If you can swing the cash, the more recent Roland XV series is much better for piano sounds, as you can put an SRX 2 or 11 piano board in it. Both of those are two of the better sounding synth pianos.
I should also mention
the Emu Proteus 2000 series synths. I have a couple of these, including the "Vintage Pro" which specializes in retro electric piano sounds. The Proteus 2000's also take expansion boards.
My Vintage Pro has
the Holy Grail piano, and the B-3 expansion boards, making it a really killer keyboard module. The only problem with these modules is that the expansion boards becoming scarce and getting expensive used, which is the only way you can buy them now.
