You can make some nice conversions by rewriting the SIMMs using the DS CPS3 Multicart.
But no multi (without some major/crazy rework and even then prob not) support.
Maybe at some future point @Darksoft could officially support the all-in-one CPS2?
He did just make the 8x sized SIMM, to hold ALL the game data for CPS3 system... Perhaps the same method could be used for a massive CPS2 SIMM?
SIMMs are for 68000 cpu code actually.
The ones using SIMMs for the grafx parts are some of the later regular CPS2 releases such as Progear and Mighty Pang.