ConsoleID only ever needed a DSiWare to be exported afaik. There was something else like "card identifier" or something that needed a game like Biggest Loser though.
Why or? Is there now a way to extract ConsoleID without NAND hardmod?
Once you've got that, you should grab your ConsoleID from a DSiWare export. Simply copy any game to your SD card and use dsi_srl_extractor with the option --basename=[name].
Open [name].footer up in a hex editor and search for 'Root-CA00000001-MS00000008-TW[somenumber]-[anothernumber] .
The number after the dash is your ConsoleID. It'll start with 08201 on DSi, 08202 on rev2 DSi, and 08A20 on DSi XL.