In a recent review, the sentence
“Now, Tanaka-sama is eating. [honorific]”
was translated to
今田中様がお召し上がりになっています。
Using Genki, I learned another progressive form: ～ていらっしゃる, which would, in my opinion result in the following translation:
今田中様が召し上がっていらっしゃいます。
Would that also be correct? Does it sound “natural”? Should it perhaps be included as “correct answer” in the BP reviews?
I mean, why not go all out and make it おめしあがりになっていらっしゃいます?
(don’t take me seriously)
I see, so you are saying that those “doubled honorific expressions” are not used, because they are politeness overkill? Even in Japanese? 
Thanks for pushing my nose in it.
On the other hand, better be prepared if one day you find yourself drinking tea with the emperor… 
Wait one sec…, wouldn’t
“今田中様が 召し上がっています 。”
be an appropriate expression, too?
“今田中様が 召し上がっています 。”
召し上がっていらっしゃる
Are correct. 
お召し上がりになっていらっしゃる
Is also correct.
By the way, you can read this topic you will find it interesting.
(Basically while お召し上がりになる is technically double keigo, but due to the tradition and wide use it is considered correct, and お。。。になっていらっしゃる is not considered double keigo, but 敬語連結 and it is grammatically correct)
Many thanks for the explanations!
Could you please include “今田中様が召し上がっています。” as correct answer in the お～になる grammar point reviews, then?
Is there a Japanese term for “death by keigo”? 
Done
Is there a Japanese term for “death by keigo”?
Something like 過敬語死 maybe 