QUOTE(MrBungle @ Nov 1 2010, 10:03 PM)

Have you also tried going back to the modded console after playing something on the non-modded machine? I recall a couple of years back having profile issues between machines and it usually gave corrupted profiles after playing on either machine and saving during a game. Then once swapped the profile became corrput again.
Still hesitant to try this if I either save games or get an achievement on the Kinect machine, and then switch my profile to the modded box.
Your profile may have been corrupted in the past because the modded console had been banned! Once a console is banned from live, it will corrupt the profile and any saves you try moving off or onto the console or onto any other console. (Not to worry to much though, as you can just recover your profile through live onto any non-modded console with no effect). Once a console is banned, it and the content on it cannot interact with any other console. (Please note, corruptions can occur for other reasons than just a banned xbox, however a banned console will always corrupt the data)
If you are worried about getting banned and you wish to keep using your xboxlive arcade content, movie streaming capabilities etc, it is generally a good idea to move all your licencing to that console before the ban happens. This way all the content is usable offline (There is a link on xbox.com that will tell you how to do this. Note it can only be done once a year).
In regards to the original question, yes the profile swichtes are currently working. Until a console becomes banned I can't see any reason why this won't continue to work (So if you have a modded and un-modded console I would keep the modded one offline until more is known). In saying that, the people that know what they are talking about have suggested that future forced dash updates on some game disk could potentially cause a problem with this. It would be pure speculation at this point to know whether this will cause any data transfer issues between non-banned consoles.
QUOTE
Still hesitant to try this if I either save games or get an achievement on the Kinect machine, and then switch my profile to the modded box.
Umm what would you be concerned about? Just make sure you log into live to update your achievements on the Kinect machine first, then move the profile to the other console. From that point on, even if it corrupts, so what. It would just be a matter of doing a Live recovery for your profile on the Kenect machine (make sure you know your email address and password for the account though). You will corrupt and lose your save game however, but not lose the achievement or profile as these are stored on M$ servers.