Ah, ok. Never were in the situation that I had to export 65000 items with "Export to Excel".
Does it also crash for 10000 entries? Keep in mind that the old xls Excel format just support 65536 rows! Maybe you run into that limit?
Instead of directly manipulation in SQL, you can also just do a simple SELECT query on your table or take a look at the ItemType table itself. This way you can simply copy&paste the shown result to an Excel file that you can use for batch load. A simple SELECT (=get) of data has a low risk of destroying data. But you still need database access.
Maybe another approach: Copy via Method? Get your previous item, get the values and use these values to create a new data entry into your new item. Not the best approach regarding performance...