McCormack DNA amp options....

I used to own (wish I still did) a DNA .05 that I had upgraded to the Rev. A. It was (and still is, I'm sure)an outstanding amp in every respect. SMC is very easy to deal with and Steve is easy to get in touch with. I wouldn't hesitate calling him at all. I have changed amps several times just to get different flavors for my own experience, and unfortunately I couldn't afford to keep the DNA and buy anything else. Still I have nothing but fond memories...

My op.
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I truly believe that the DNA .5 is overall the best sounding of the McCormack series (and yes, I have owned them all, in fact, a few more than once)The upgrade to Rev.A will remove the remaining tiny little bit of grain and allow for a touch deeper soundstage. One caveat, the revision does make changes for the better overall but it is not a leap into nirvana. I have known some who didn't like the revision when they got it back. Whether they gave it sufficient break-in I don't know. It does make a difference. Before, and I know, like me, you like McCormack, you might want to look at a few more amps before you spend the money.
To give you an example, I was using a pair of DNA .5 Deluxe amps to biamp my Vandersteen 3A Signatures. I was using an Audible Illusions preamp. I too, contemplated upgrading the 2 amps at a cost of about $2800 at the time. The amps themselves sold for $1495 each and had a current market value of about $700. I decided after reading Richard Hardesty's review of the Theta Dreadnaught to purchase one and give it a go. Man, what a move. I went with 4-200 watt modules for biamping. It was probably the best move I ever made. It enhances the basic McCormack sound to a genuine higher plateau. More transparency, bigger soundstage, pretty much, you name it. I then tried a borrowed revision A McCormack. I went to 2-ch on the Dreadnaught to make it fair. As much as I hate to say this, the comparison ended pretty quick. The bottom line for me was, the 4-ch Theta cost me $3900. A 2-ch at the time was $2700. These are with discounts through the "Sound Broker" brand new in the box. The Theta is a better sounding amp hands down!
The point is, I would look around a little before spending the bucks.
As for converting to a mono block, I would just go with the DNA 1. Even though I don't feel the DNA 1 sounds as good in direct comparison to the .5, you will negate some of the sound of the .5 doing this to where they both will sound similiar.
The new DNA's are excellent amps but I feel do not sound overall as good as the older amps. The new amps use a DC blocking cap in the input and you can hear it. They simplified the circuit somewhat.
Just my opinions for what there worth. I'm sure someone will come back with some other ideas.

With 93db efficient speakers, I question the need for another amp - much less a conversion to monoblocs on top of that. (You do realize you can use two stereo amps on a pair of speakers without converting them to monoblocs.)

IMO, you would be better served allocating that money to upgrading your existing .5 to the max - Rev A Gold. In particular, you can now get the Plitron toroid transformer for the .5 which significantly improves bass performance (among other things) and makes the .5 seem even more powerful. Also, I would strongly suggest the soft recovery diode upgrade. You won't even recognize the sound of your old amp after these upgrades.

One other thing. If you still want more power and upgrades, I would stick with adding a .5 versus just getting the bigger models. The primary reason is that shipping a .5 to get upgraded does not require crating and is much less susceptible to shipping damage via regular means. In addition, two DNA.5 probably sound a little better than one DNA 1 due strictly to the traditional benefits of biamping.

Just call Steve and talk to him about your possible options. He is very down to earth guy and I'm sure he will give you all your pros and cons.

Jose.

I'm taking the upgrade plunge, or rocket. I just purchased two DNA-1 amps that were originally produced as mono-blocks and had them sent to SMc for the rev A+. My speakers are Eggleston Andras, which are power hungry, thus I chose the 1’s over the .5’s. It actually costs about the same to upgrade two 1's for mono rev A as it does to upgrade one 2 for rev A.

two DNA-1’s 1,500 (for two amps)
mono conversion 450 (per pair)
rev a upgrade 2,400 (for two amps)
total 4,350 (of course now you have to look at used Pass X-350’s and so on for this price)

one DNA-2 1,250
rev a upgrade 2,950
total 4,200

However, the difference between two .5’s and one 1 appears to be more substantial:
Two DNA- .5’s 1,000
Rev a upgrade 2,000
Mono conversion 450
Total 3,450

One DNA-1 750
Rev a upgrade 1,200
Total 1,950

Rather than upgrading your current .5, you can look for a used .5 rev a. I see there is one pending sale here on agon for 1,200.

For me, I’m very optimistic about a mono config's ability to better handle the low-end frequencies. Plus I admit, I just like the idea of two amps. Just thought I’d share my reasoning with your similar questions on options. Until I actually receive the amps, that’s all I can share. It’s a tough call to purchase a product and service/upgrade based solely on personal reviews and reputation. Crossing my fingers.