Thanks everyone for your quick help.

I have started to look at 20in carry-ons with wheels. It would be nice if internal dimensions were included! So, I am taking some rough guestimates on what the dimensions are.
This should not be this hard. But, I guess it is when you have very specific requirements.

@tfar That is exactly what I was thinking about the mods for the Air Boss. I just cannot believe they have not though of this yet...I even asked the guy on the phone.

@Megyn Do you think a bag like the Air Boss would be help securely enough by the travelon bungee?

Here are the bags I am currently looking at for carrying the clothes:
Antler

B&R

I have been doing more international travel and I am wondering if this will meet the Heathrow check?
TLS

Any thoughts on the sizes and recommendations?

Bottom line is that I need the largest carry-on capacity I can get as long as it can get on wheels somehow. If that is strapping the Air Boss to a laptop wheeled bag or doing one of the above, this what I have to do.

Thanks again for your help!