Absolutely. I use foundationless frames in many types of hives.
But.....where should one just abandon the whole Warre concept, in favor of just another hive altogether?
I built the Warre as per the established protocol. And I guess each needs to modify as one See's fit.
I think a smaller hive, such as an 8 frame hive with standard frames, foundationless, moisture control and NO upper entrance, and even under supering....gives you many of the advantages that Warre spoke of, but yet allows standard equipment, and an ease of management with removable frames, etc.
I think the problem I see, is the following of rigid protocol as Warre outlined. I would rather see others learn from his writings, while implementing specific advantages into more manageable hive designs. I think Warre hive had many great observations. But for some of the positives, there are some negatives involved. So for each of these items, is it important to be so rigid that perhaps small changes would be beneficial, yet lost on the fact that some say that these changes "might" change something so drastic to make it useless? I don't think so. To suggest that it is stressful for bees when the hive is opened, may be correct. But does that mean we need to totally skip the enjoyment of opening a hive and showing a visitor the bees? What I like to think, is that we should be aware of the damage we do to hives by our manipulations, etc., and tailor our practices to minimize them. But not totally go off the deep end by suggesting detrimental damage will happen each and every time we open a hive.
The Warre hive purists may not like this approach, but I think that is the best approach.