I spoke with Mark Dettlo, the service manager at Muller's Woodfield Acura, to alert him to the issue regarding using the combination water pump and timing cover on NSX timing belt changes. He's looking into it. I also asked him if he'd be interested in providing a price that people could rely on for a timing belt and water pump replacement on an NSX, and he said he'd get back to me. He also noted that they currently have a service special, with $200 off on any timing belt service; you can find the coupon on their website
here.
In the meantime, here are a few assumptions that seem reasonable to make regarding pricing of a timing belt change. If we take the estimate Tangoman received for $2403.25, then substitute these two parts:
19200-PR7-A03 $414.87 WATER PUMP ASSEMBLY
11810-PR7-A02 $224.33 TIMING COVER
for this part:
19200-PR7-305 $322.57 WATER PUMP ASSEMBLY SET
that lowers the parts price by $316.63 before sales tax, or $345.13 after tax. Subtract out the $200 coupon special, and that puts the total at $1,858.12.
I will report back if he is able to quote anything specific when he gets back to me.
P.S. I apologize to Tangoman for doubting him regarding the use of the combination water pump and timing cover rather than the separate parts, and for the language which I used in my previous post.