R4 and/or Nimbus. The Relab emulation is also very very good.Maybe a useful suggestion, maybe not- Michael Carnes, who worked at Lexicon for 25 years, made the Exponential Audio reverbs. To me, they're basically the next step for the Lexicon sound, and they're frequently on sale from Izotope for very, very low. I would demo them to see if they fit your workflow and if they do, wait for a sale. The name scheme is a bit annoying, but R4 is what you want.
I think Nimbus is more for natural world reverbs. I think R4 (as you mentioned) or R2 (less tweaking parameters than R4) are the ones with the emulation of digital and Plate reverbs. I could be wrong.R4 and/or Nimbus. The Relab emulation is also very very good.
But... the $50 Valhalla Vintage Verb is definitely a reverb highlight in this same realm as well - and may even be the sweetspot imho