I'm wondering if SoftMPU could be extended with a translation mode to translate the MT-32 SysEx messages to D-110 ones. This would enable using one of the later LA synths that have a different instrument/patch order to work with games only supporting the MT-32.
There are SysEx files to make those syxnths MT-32 compatible, but games loading custom instruments/patches won't work because of the differing order. An ad-hoc translation layer could maybe fix that!