I merged my QBO and QB Pro into a single file with these guys:

quickbooksrepairpro.com

I needed to make a backup for pro.

I needed to export QBO to "desktop"

I paid them their fee and the took the files.

a couple days later I got one file back with ALL the datain one file.

uploaded it to QBO as a new company, setup my prefrences (HIGHLY recommend two screens, open the original QBO on one screen and with another browser on the other screen)


Then after a week of using the merged file I deleted the old QBO.

sure its a pain to setup incoice templates and a few other things... but worth it