But not according to Rashi!
The first instance in the Talmud where k'vyachol appears is in Yoma 3b:
קח לך משלך ועשה לך משלך ויקחו אליך משל צבור דברי רבי יאשיה רבי יונתן אומר בין קח לך בין ויקחו אליך משל צבור ומה תלמוד לומר קח לך כביכול משלך אני רוצה יותר משלהם
Here is the Soncino translation:
The expression ‘kah leka’ means ‘mi-sheleka [from thy own] and ‘aseh leka means mi-sheleka [taken from thy own funds], but we-yikehu eleka means [they shall take for them] from community funds; these are the words of R. Josiah; R. Jonathan said, Both ‘kah leka’ and ‘we-yikehu eleka’ mean from community funds, and what is intimated by saying ‘kah leka’ [take thee]? As it were, ‘I prefer your own [private means expended on this work] to the community's [expenditure]’.
In other words, although God did not actually disfavor the Jewish People's offering, it is described as though that was actually the case.
But let us look at the definition of k'vyachol provided by Rashi:
כביכול - אני שמעתי אם היה ציבור יכול להתכפר בשל יחיד הייתי רוצה, ואני אומר לפי שדבר קשה הוא לומר שהקדוש ברוך הוא קץ בישראל, אומר כביכול, כלומר על כרחינו יאמר כן, כאילו (אי) אפשר לומר כן, וכן כל כביכול שבתלמוד:
Amazing! Rashi explains k'vyachol to mean that the concept is "difficult for us to say" - for who wants to say that Hashem is undesiring of the Jewish People's offering? However, "against our will it is thus stated" - even though we don't like to hear it - "as though it were possible for us to say it." It's not "as IF it were true" - it IS true, but we hate to say it. It's not "following a manner of speaking" - it is the correct description.
Ritva elaborates upon Rashi's explanation:
כביכול בשלך אני רוצה יותר משלהם הפי' הנכון כפי' השני דפרש"י ז"ל דאמרי' כביכול מפני שהוא דבר קשה לומר כי הקב"ה קץ בקרבן צבור אלא דכיון שכתוב בתורה יכול אדם לאומרו וקרא ה"ק קח זה הקרבן של צבור ויהא חשוב כאלו הוא שלך שאני רוצה בו יותר:
Of great significance is that Rashi concludes his explanation of the term by saying that "such is the explanation of every occurrence of k'vyachol in the Talmud." Let us now turn to another occurrence, Megillah 21a. This is discussing the chiddush that when reading from the Torah, the one reading has to stand, which we learn from the Torah's description that God stood together with Moshe when teaching him the Torah. It goes against what one might consider to be the appropriate protocol; after all, when one goes to meet a king, the king remains seated while the petitioner stands.
אמר רבי אבהו דאמר קרא ואתה פה עמד עמדי ואמר רבי אבהו אלמלא מקרא כתוב אי אפשר לאומרו כביכול אף הקדוש ברוך הוא בעמידה
And in the Soncino translation:
R. Abbahu said: Because Scripture says, But as for thee, stand thou here by me. R. Abbahu also said: Were it not written in the Scripture, it would be impossible for us to say it: as it were, the Holy One, blessed be He, also was standing.
But this is not Rashi's explanation. Here, Rashi's comment is brief:
כביכול - נאמר בהקדוש ברוך הוא כבאדם, שיכול להאמר בו כן
But following Rashi's explanation in Yoma, which he says applies to every occurrence of k'vyachol, we see his view clearly. The concept is "difficult for us to say" - for who wants to say that Hashem, the King of kings, stood together with Moshe, whereas a mortal king does not lower himself to stand with his subjects? However, "against our will it is thus stated" - even though it is discomforting vis-a-vis Hashem's dignity - "as though it were possible for us to say it." It's not "as IF it were true" - it IS true, but we hate to say it. It's not "following a manner of speaking" - it is the correct description.
Thus, here we have yet another argument in favor of the proposition that Rashi had a corporeal view of God.
Rabbi Zucker, who continues to argue with me in the comments on this post, unsurprisingly rejects this argument. He claims that there is no issue of disrespect to Hashem here, and the reason for k'vyachol is that it is not literally true that Hashem stands. Rabbi Zucker claims that although Rashi is saying that it is true that Hashem stood, he is not saying that it is literally true, merely that it is figuratively true. (Of course, there is nothing in Rashi here that leads him to this explanation; he is saying it due to his conviction regarding Rashi's position which he claims is based on other sources.) Thus, he is explaining Rashi as follows: "It is difficult to say" that Hashem stood, because He does not literally stand, "but against our will it is thus stated," because it is allegorically true.
However, this is not at all viable, for two reasons. First of all, Rashi explains k'vyachol to mean that it is being stated "against our will" - i.e., we do not like the Torah's description. But why would we not like the Torah using an anthropomorphic expression in speaking about God as standing? The Torah uses anthropomorphic descriptions of God all the time!
Second, Rashi is explaining the Gemara's statement that "Were it not written in the Scripture, it would be impossible for us to say it." But if it is not literally true, it would not be impossible for us to say it! We use such anthropomorphisms all the time. Is it forbidden to say to someone that "Hashem will be happy if we do mitzvos," when it is clear that one is speaking allegorically?!
Thus, Rashi's view on k'vyachol, which is radically different from the conventional understanding of this phrase, serves as excellent further evidence for his being a corporealist.
(I would like to thank Rabbi Zucker for pointing me to this Rashi, although he probably regrets doing so!)