Column/cells to single cell comma separated data?

Hi all!

I think this might be an easy one for the Excel gurus here on this board!

Here goes:
I have a column of job #s that I want to combine (separated by commas) into a single cell.

I am looking for a quick method...

I know how to <copy--paste special--transpose--save as CSV--and open with Word>.

I can also get the effect I am looking for by doing:
=CONCATENATE(A2,",",A3,",",A4,",",A5,",",A6,",",A7,",",A8,",",A9,",",A10) ETC.

But only on a small scale (up to 30), I need to combine up to 30,000 cells at times, so I don't think that "Concatenate" is the real solution here.

Any suggestions are much appreciated! Thanks.