Hi Eril,
Thank you for your post.
I do like your idea on not using a preamp in the signal path, but regarding a remote option for the Sig 70s, I don't offer this on my site because I wasn't sure if controlling the volume of both monoblocks at the same time would work perfectly 100% of the time. If you were to stack them and use one remote, they *should* both see the remote signal and be "in sync" (and I'm not talking about the boy bad n' sync!

). If by chance one monoblock were to see the signal while other other one did not, even for just one "click", then one channel will be a tad louder than the other. You would have to manually increase the step of the lower side and then they should be back being equal when controlled via the remote.
Based on testing two different Signature 30 amps with remote control option, stacked together, one remote seemed to work fine as long as you aimed the remote at them and didn't have anything blocking the IR sensors on the amps. From time to time, you still might want to check that they are in equal positions.
The remote control kit that I use is the one designed and built by Bent Audio for the DACT stepped attenuators. It is very high quality and as I mention on the Sig 30 website:
-- Direct coupled stepper motor using custom machined mount and coupling
-- Any universal remote can be programmed to run the board
-- All clocks shutoff and go into 'sleep mode' between commands for EMI/RFI noise free operation. NOTE: The remote control option does NOT effect the sound quality in any way.
I talked to John at Bent about the possibility of having one monoblock have the IR sensor, and it would feed that unit and a hard wire would connect to the other unit to control it at the same time. He didn't suggest doing this and was concerned that there could be hick-ups when trying to drive two of his remote board from one IR sensor.
My Sig 30 doesn't have a remote volume because I use a squeezebox to control the volume.
The SB is modded by RWA but Vinnie has switched focus to the Olive players now... with the Nokia 770 you could even browse you album art from your seat!
Fu_man is doing what quite a few of my customers are doing (a nice approach IMO!). The use their volume controlled source to feed their Sig 30 or 70s, and set the volume control on the Sig 30 or 70s to a fixed position that gives them the best useable range of volume control out of their source.
And yes, you can use an active preamp with remote volume control as well. Your results may vary depending on the quality of the preamp in the chain, but there are good ones out there (but they ain't cheap!).
Best regards,
Vinnie