Let me start with the caveat that I mix entirely in Pro Tools.
Clearly my thinking is small potatoes in comparison to an MPC (as Stavrosound mentioned) or a DFC, but I also have no experience to speak about regarding theatrical dub-stage mixing.
Additionally, as I was writing, my answer kind of evolved into an answer about business purchases in general, with an answer to your specific question tacked on the end. Sorry if I ran off the rails a bit, but it's a topic that has been on my mind lately.
I love my D-Command, it's the most advanced mouse I've ever used. The integration with PT is fantastic and I love its Custom Faders. The quality of the materials it's made with are decent, but not outstanding. I've been using this one in front of me here for five or six years and it's barely showing signs of aging. I think one fader has died, another is in need of attention. But a) they're easy to clean, b) they're easy to replace. I could see swapping out the stock faders for something a little nicer. But, in this facility, that's a decision that's currently outside of my pay-grade. Honestly, I don't even know if it's possible.
No money restrictions is a tough mind-set to put myself in. Even in fantastically-hypothetical situations like the one you're proposing, in the end, I'm still a business owner. And there is a point of diminishing returns. I'm always going to consider the value I receive for each dollar I spend, and the difference in potential earnings that all of my options can provide.
There is a point where you've gone beyond what you need and are approaching what would be freakin sweet. The question is, does the caché of freakin sweet have the potential to bring in more revenue than what you need? How much more? Enough to front the cash for it? Then go ahead and pull the trigger.
Another thing, note that I said "front the cash," not "afford the payments". This is obviously an entirely personal business decision, but advice I received from a business associate whom I respect very much told me once: "Always pay in cash. If you don't have twice the price in the bank, it's outside of your budget."
Having said all that....
With a substantial budget, I'd probably investigate a D-Control. After all, it's one level better than a D-Command, right? But with that same business-owner hat on I'd be a hard sell. See, I'd also be considering spending about half of that same $60k on a D-Command + fader pack, surround panner, and an Argosy console to put it all in. In my opinion, that competes pretty well with a D-Control. Then with the remaining $30k, I could invest in additional HD Core & Accel cards, additional I/Os, upgrading my speakers, hiring an assistant, etc. All of which can increase the overall quality or speed of turnaround on a project. Which in turn has the potential to increase my number of billable hours, expand my client base, and ultimately bring in more revenue so I can afford other pieces of gear/people that will do the same (or take me & the Mrs. on vacation cause I already have everything necessary to compete in the marketplace).
One thing that I know I'd take into consideration is ergonomics. For example, the reach to the top of the board. With the D-Command, it's a full arm extension from my seat with no lean-in. That's nice. You're going to spend a lot of time in front of this thing (hopefully), try to make it as pleasant an experience as possible.