You can't change the data type for when using the ACE drivers; they're "nice" (a pain in a*se) and decide what they think the data is for you (normally based on the first 5-10 rows).

If you have the ability to amend your spreadsheet before import, I suggest changing the data format of the column to "text". Is that something you're able to do? The ACE driver's should then read the column as string, rather than trying to interpret it as something some of the rows are not.

If not, then I do have a solution, however, it is not pretty (and involves building your own Script Component as a datasource).