ok

GG5: "お取り込み中と見えますね． You seem to be awfully busy.:
Eijiro: 
■取り込み中すみませんが… : I'm sorry to interrupt you, but ...
■取り込み中で : in the middle of something
■取り込み中で {形} : busy
■取り込み中です : I'm busy.

It's pretty common (n-grams 155k) and seems almost always to mean "busy with something", which is not immediately obvious from 取り込み itself. I think it's best kept, but with the other senses Richard suggests.

@@ -17 +17 @@
-<pos>&n;</pos>
+<pos>&exp;</pos>
@@ -19,0 +20,3 @@
+</sense>
+<sense>
+<pos>&exp;</pos>
@@ -20,0 +24,3 @@
+</sense>
+<sense>
+<pos>&exp;</pos>

I agree, it's a construct and should be deleted.
As with my submission for 一番下, I am pointing out that if the entry is retained, it needs more senses to be added. 
There are other constructs in EDICT, so I wasn't sure what the policy is.
I see 一番下 has now been deleted, so it seems that there is a trend to get rid of constructs that were accepted in the past.

is this entry necessary?  another construction.  and there are multiple senses to 取り込み.

"in the middle of something; busy" could refer to some routine procedure. It just means that one is occupied with something.
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But 取り込み中 can be an indication that something that is not routine (like a mishap) has happened:
取り込み中:
平時とは異なる様子でばたばたしているさま。紛糾しごたついているさま。他のことにかかずらう余裕がないさまを表す際に用いられることが多い。
http://www.weblio.jp/content/取り込み中
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The following example from gg5 is 取り込みごと rather than 取り込み中, but it illustrates the connotation of misfortune that 取り込み can have.
鈴木君の家では何か取り込みごとがあったようだ. It looks as if there's been some trouble at Suzuki's place.
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Also 新和英中辞典 defines 取り込み as [...] 2. 〈混雑〉 activity; a bustle; confusion; disorder; 〈不幸〉 trouble; misfortune [...]
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OTHER EXAMPLES
1) busy:
Each of the contacts listed is labeled with a status indicating their presence and availability, such as "Busy," "Away," or "Out to Lunch."
一覧内の連絡先にはそれぞれの在席と予定を示すステータスのラベル "取り込み中"、"退席中"、または "昼休み" などが付けられます。
2) IT usage:
画像取り込み中、カメラのLEDランプ（ 緑）が点滅し、モニターに「Capturing（取り 込み中）」が点滅表示されます。 
While the image is acquired, the camera LED flashes green and the word "Capturing" flashes on the monitor.

@@ -19 +19,3 @@
-<gloss>busy</gloss>
+<gloss>busy with something</gloss>
+<gloss>in commotion as a result of something untoward happening</gloss>
+<gloss>currently importing or capturing data</gloss>