Plant expression of therapeutic proteins

What do you think of this? Butler presentation on plant-based protein expression coming of age.

It was news to me that this is possible (it looks like tobacco spp is the plant in question). And they cover how the plant glycosylation makes this crap for ADCC and the like, but that the glycosylation can be "humanised". Don't ask me how you do that, but I guess it's in vitro, post-purification chemical modification of the Ab? Or is it actually possible to tweak glycosylation by genetic modification of the organism producing the protein? I don't remember how all that works: endoplasmic reticulum blah blah blah.

It's possible that camel antibodies or camel-antibody fragments (http://en.wikipedia.org/wiki/Single-domain_antibody), with their easier folding, simpler structure, greater stability, etc, would actually be even far better candidates for plant expression than other antibodies and proteins. For example, it's possible that whatever relatively harsh extraction techniques are needed to get the Abs out of the plant mush are less likely to denature the camelbodies than other Abs. So it's possible you get both greater yield in the plant, from ease of expression and folding, and also greater yield out the other end of the purification process.

My other question would be is it possible to use another plant species that does a sort of compartmentalisation of tissues. For example, if it's possible to get corn plants to express a given protein at high volume into the corn kernels/fruit, then wouldn't it possibly be easier to harvest the protein, if you only have to purify it out of a fruit-like tissue (with hopefully simple biochemistry e.g. mostly starch) and can throw away at the beginning all the green stuff?