Mike,
It sounds like you want it all!
(Or, you asked for it so here it goes....)
NOS:
Non-oversampling is the answer if you hear that weird, digital sibilant edge to things that you can't quite put your finger on... It's not a big deal unless you hear what the NOS DAC does that removes the 'issue' you didn't know you had. The best oversampling dac's I've heard still have that digital-edge to the 'corners' of the sounds. The worst is female vocalists... whatever frequency range that's in, is the upsampling DAC's downfall.
Some will not be bothered by this and will enjoy a slight increase in overall detail... and extension. I'm in line for a new, NOS tube DAC with XLR outs, and all the popular inputs. I've heard the predecessors and they've really come a long way over the years. So, I'm not giving up much when I go this route... and I'm gaining that NOS sound that once you decide sounds more like real music, you have no choice but to stay with it.
TacT Gear:
The TacT became the PRAT-master, after Anthony/Aberdeen did his mods to the board and DAC. Transparency and detail were also greatly improved. I enjoyed the room correction capability but in the end I sold it in favor of that NOS sound... and to add a turntable easily into my system. If you like your TacT now, please send at least the DAC to him to upgrade... and of course, the power supply.
However, it sounds like you're going to the NOS-side. So, no level of perfection is going to beat what sounds more like real music, in your room.
Hantra and I have been doing comparisons every few weekends of our systems and finding our likes/dislikes... and he put it best... and I'm paraphrasing... "with the NOS, it sounds more like what I want to hear as a performance in my room... whereas with the upsamplers, it sounds more like what the recording engineer hears." So, which is better? That's up to you.
EQ:
I think room correction is best done physically. As in, buying a house with a room dedicated to 2-channel listening, with all of the best principles employed, to your tastes. I may like more absorption than the next guy, maybe less. But, using bass traps, corner treatments, etc. are mandatory.
Now, for the 90% of us that can't do that, there's electronic EQ. In my opinion: You can't have perfect microdynamics, absolute transparency, etc. AND have an electronic processor in the chain. However, the benefit of 1, will outweigh the other... So, having EQ in a room that really needs it is worth the other (small) compromises.
So, the answer is yes, you can have your cake and eat it too especially if you are ok with oversampling dac's like the TacT. If you use the old-school EQ, man... I don't know... I've never heard one that was worth the compromised sound quality... but it may be out there.... I've never heard a Behringer setup, so, I'm not sure if those would be a better NOS-EQ system for you or not.
-C