Hey all! Important news--I found a way to get the bonus items without cheating. The method requires Dolphin and Visual Boy Advance, and the requisite ROMs and ISOs. I found this quote on a Dolphin forum:
Thanks to you,guys,i was able to transfer the special items from the Double Dash Bonus Disk to a dumped copy of my Fire Emblem.After all these years i finally got that Bonus Disk! I ran it on Dolphin and set controller port 2 to be GBA (just like the real Gamecube!).Then i used Joybus link option on VBA-M (Bios enabled) and the transfer ran smoothly.I got all the special promo items in my FE game without any cheating! For me who couldn't buy a Gamecube,Dolphin was my salvation.Thank you very much,Dolphin team!
Again, I'll try this when I get the chance.
EDIT: It seems you actually have to use Visual Boy Advance Merge, which has the "Joybus Link" option.
Edited by Gaggle of Geese, 05 July 2012 - 02:07 PM.