I am French and I am also an emacs user who prefers to have symmetrical alt keys for ergonomic reasons. As a result I am used to switching from AZERTY - which has an altgr key - to US QWERTY when using emacs.
I can see that Colemak is a great improvement over QWERTY and DVORAK, and having multilingual support is great. You can even type French characters with Colemak that you cannot access with AZERTY, i.e. æ, Æ, œ, Œ, É, Ç. But I would prefer to be able to switch between a -missing?- US Colemak layout and the regular Colemak layout.
Having to type Meta+key combinations is indeed much more comfortable when the two corresponding keys are located on opposite sides of the keyboard. I think that is why Colemak soundly places most international symbols on the left-hand side.
I am wondering what are the best solutions some users could have found in order to temporarily change Altgr to Ralt in Windows.
I hesitate to learn Colemak (other optimized-layout alternatives could be dvorak, workman, or the French Bépo layout). Having this Altgr issue is a no-go for me in case there was no workaround - and switching to gvim or viper mode is not an option.