(before you going further i must say this is actually another brand 10+ years old flashcart, just hope maybe this can be usefull to krikkz...)
(this is kinda a joke thread.)
I got my hands in this amazing flashcart, the awesome gba x7 Lite version.

what does the "Lite" mean? it fits a ds lite perfectly!

as you can see even has a ds lite shell that ressembles the ds lite dust cover!
this flashcart is capable of rtc, has a ingame menu (via software patch) which does support real time save! (aka snapshots)
does load 32MB roms, it's not instant, but it's not ez iv psram slow!, has stuff like video and mp3 player.. (but who cares about theese) it also supports DS mode, with DS game loading... but again, who cares about theese... ho, and rechargeable battery! (however it holds like 30 minutes charge only now, i am looking to swap it)
sadly the biggest con is no sdhc support (this card is old...)
this is an m3 perfect lite... it was the "holy grail of gba flashcarts"
the everdrive gba x5 made this card irrelevant, the everdrive is a lot better, but i am kinda upset because the x5 size (like plenty of people..)
krikkz, props to your cards usually have the sd card slot in a place where we are not required to remove the everdrive from the device to swap memory cards...
krikkz, if ya want, i can try to shoot good pictures of this card, or tell you what's written in the chips to help you in the designs of next card
but i guess that easily swapabble battery holder in the evgba x5 + top loading sd card made it the size it is...