Ya, all the daughter card options out there have their problems. I don't know how many companies created NOR (FlashAdvance2 and Ezflash Trinity/3 in 1) or alternative methods (M3 Perfect, 'ram'?) to upload GBA games into a primary memory... But at least if you can find it adds the ability to use link play for 90% of the games that offer it.
Super Card had their own daughter card, but I haven't heard anything about its features compared to the others. Or if had NOR or not...
If Krikkz made a DSi/DS card, I'd love if he made it compatible with DSi code (for all the white games, and all the grey DSi bonus features games), if he figures a way to allow it to bypass 'region lock" (so that any DSi game from any region could be played, not even 3DS flashcarts can do this unfortunately) that would be even better. Note: Any DS flashcart will allow "grey dsI' carts to work but it only loads up the classic DS compatiblity part of the game (no DSi) features (as the game would work if it was played on any DS Phat or DSLite).
I think he should also sell a 'daughter card' simply for purpose of accessing the DS Lite Options Pak features (some kind of premium 3 In 1 type card, with rumble, expansion ram, and NOR or equivalent), but also make sure to add compatiblity with ram types so Pokémon and few games that transfer 'data' over can use it. As an added bonus maybe toss in sun sensor for use with the four Boktai/Lunar Knights games and their link/connectivity as well. We can only dream, but also add some of the features from other Options Paks sold as 3rd party (Motion control?).
Plus maybe compatiblity with rumble games and motion games both in GBA and DS like; Tony Hawks Motion (DS), Drill Dozer (GBA), Yoshi's Topsy Turvy (GBA), Wario Ware Twisted (GBA Rumble + Motion), Koro Koro Puzzle Happy, etc. And also make 'rumble' work directly with official carts if you own them too (something most of these 3rd party daughter cards don't allow, official carts can't communicate with the daughter cards).
Wishful thinking, there isn't likely to be a !00% compatiblity fix...
Alternatively, at least for the Pokémon linking it might be possible for someone to patch the ram type in the game itself (either on the DS game side or the GBA game side, or both?), or make some other way for card to see it? That could be useful... Someone hinted at a way to get Pokémon games linking to work I think, but it's definitely requires some hacking of the roms, I think? I need to check into that.
I did further research on the pokemon games and just as I expected the generation IV games is looking for the savegame information in the FLASH. Since none of my GBA Cards has flash storage, Pokemon Diamond refuses to see the pokemon savegame (out of the box). There is, however, a tool that allows you to patch the DS Pokemon games to look in the SRAM section of the GBA cart, which I got to work with my 3in1 and F2A as the patches are specific to the slot-2 flashcard used. I was not able to get it to work properly with the EZFlash IV even though the pokepatcher tool said it would be compatible, I got the option to show up but it would tell me the save data was corrupted.
Depending on how the EDGBA works with its savegame storage the DS games *might* be able to work ootb or *might* be patchable with pokepatcher.
You apparently have to use something called pokepatcher.
The only other games that might need to be patched, as they offer some kind of 'transfer' option is some of the Mega-Man battle network games I think. And Pokémon Dash, not sure if that one is included in Pokepatcher.
