The good news is that I've successfully dumped both, the bad news is that both have to be cracked before they work. The SNES one has a protection scheme similar to all the other DVS titles, or at least the error messages are the same. Mega Drive version is strange, it almost acts like the cart shifts country protection schemes (amongst other odd things) soon after booting up.
The Mega Drive one is fairly interesting. The game engine is a slight bit tighter than Samurai Spirits II, but not by much, it does not play as good as KoF '98 or anything made after. No new sprites, they're all taken from either SSII or Soul Blade. The backgrounds are actually really nice, they're either original or ripped from sources I can't identify, one or two of them have some minimal animation. The presentation is actually probably one of the best looking of all the unlicensed fighters for Mega Drive / Genesis, too bad the gameplay doesn't match.
About the proper name, here's the odd thing. The screenshot for the MD version title screen is on that post Barver made a while back, but my game cart has the title as "Samurai Shodown VS Soul Edge", mainly because the majority of the label is taken from Samurai Shodown Anthology for PS2/PSP/Wii. The SNES cart has "Samurai Shodown VS Soul Blade", yet the actual titlescreen is "Soul Edge VS Samurai" with no reference to Final Samurai V or anything like the Sega version has.