Okay - apologies for the delay but i've dug out my old cards and have a play around with them - i have :
1) A EFA "Extremeflashadvanced"
http://www.efa.cc/index-e.htmlI have a much older version which is 512 but actually is only about 64 megabytes
Works great for just about any GBA game , I also have a 'bridge' adaptor (cost about another £10 when i got it) which lets you put GB games on the card and play them (but you couldnt do this on a DS or a Micro)
The drawback is that you need to connect the custom cable to your machine , and run a program to transfer the files and save games to and from the device , and as far as i'm aware its windows only.
It was also very expensive when i first got it and since you couldnt use it for DS games you started to see less and less of them around
Dealextreme have them listed for $20 but none in stock
http://www.dealextreme.com/details.dx/sku.104472) A Supercard SD (slot2)
The GBA compatibility on this is 'okay' but there is some slowdown in games and it doesnt handle some specific titles , i got this really as a flashcard for the DS when it first came out because it was one of the first to do DS games (all of which had to be patched to run from slot2)
http://eng.supercard.sc/products.htmIt does have the advantage that you can run emulators on here so NES / GB / etc are all great but for actual GBA games i'd give it a miss
For GBA games you can just drop them on the card but there is also software you can run to patch them (not absolutely required)
Dealexteme sell the mini sd version (so slightly smaller) for $13.00
http://www.dealextreme.com/details.dx/sku.2734 3) An M3 adaptor (old version which is the big thing i showed sticking out of my DS lite above)
http://www.m3adapter.com/SLOT-2_Series_M3.htmAs mentioned i have a really old version of this (which takes sd cards) , but there are newer ones which take both mini and micro sd
Compatibility is great although the save function can be a bit awkward (your save is in a special area on the card itself and only written back to your memory card when you turn the machine *back* on after shutting the game off) , it plays just about every game out there , and has built in emulators to play NES / GB games.
Again there is software to convert and add features but you can just drop the roms on
Dealextreme dont seem to have the older cards listed but the M3 website does list some uk sellers (
http://www.m3adapter.com/global_sell_ne ... tedKingdom) but i've not used any of them and the links are probably ancient
This place was linked to from gbatemp in December last year as a seller still with stock of the mini sd card version
http://www.realhotstuff.com/-c-36_46.html which is $36
I did also have a card which was something like Firebrand or Firebase , it was very cheap at the time and the reason behind that it was terrible , the software to flash the games on required you to plug a special cable from your GBA to the parallel port on the PC , turn on the GBA with start and select held down (so it went into some type of transfer mode) and it slowly wrote the games to the card using the GBA itself
It only worked on original GBA's and SP's not micros and the software was in terrible engrish and kept timing out , when i sold my GBASP i bundled it with it saying it was there but rubbish - it had about 4 games on though so if you just treated it as a multi game card and didnt change them youd do fine :-)
Let me know if you have any other questions on this.
** Edit ** almost forgot size :-)
The EFA card is the exact same size as a normal GBA card
The Supercard is about an inch larger , but i have the SD card version the mini SD ones are closer to the size of a real cart
The M3 i have is a ridiculous size , but the mini and micro versions are much closer to the size of a real cart