Also, the 215 can be had for significantly less than $70k US.
Why do you want a dark, mellow sound? Just because you prefer it, or is it perhaps because you want quiet to save your ears?If you just want to decrease the volume, there are musician earplugs that decrease the volume without changing the tone quality. They are custom molded to your ear.I just ordered a pair, and I can tell you how well they work for me in a couple of weeks.
If you are looking for a piano with heavy touch and dull sound try a Chickering Grand.
And Pianostudy - do tell us how old the August Forster you played was. I was just piano shopping and played loads of AFs. I found they had great tone and a delightful action (as G. Fiore notes). Also, the 215 can be had for significantly less than $70k US.