Having been rounding out my Toaplan home library lately, becoming unexpectedly fond of Tiger Heli (
the sniper tank wars begin!), I've been re-reading blackoak's excellent Toaplan interview translations (all can be found
here).
You were right Ed, MD Tatsujin was definitely handled in-house by Toaplan at Sega's request, and although I can't find definite confirmation at the moment I think it's safe to say MD Daisenpu was a product of the same arrangement. Same Same, Hellfire, Zero Wing and Slap Fight MD are all cited by Toaplan members as in-house, too.
I still wonder about MD Kyukyoku Tiger. Of the in-house Toaplan vert ports, Same Same and Daisenpu's reformatted screens feel great to me while Tatsujin seems a bit on the cramped side; I put that down to the game's heavier reliance on fast static bullet patterns and the noticeably larger ship sprite. Maybe the latter is something Toaplan resolved in the subsequent ports, SS's biplane and DSP's Zero are minuscule compared to the big orange Tatsujinmobile.
Even Tatsu doesn't feel nearly as boxed-in as K.Tiger, though. I gave it a spin after finding the AC ver on TSBv1 surprisingly easy. As expected, yep, it's way harder, but essentially due to lack of breathing space. Surprise, gunboat flotilla in your face! With this being the only Toaplan vert on the console without the "status bar on right" formatting, and no recognisable names in the credits, I'm tempted to think this was all Treco. I actually do like the claustrophobic feeling of this version, as well as the incredibly punchy explosion sfx and meatier guitar sound, but it's hard to shake the sense of battling against the formatting more than anything else.
Besides KT that leaves V-V, Snow Bros and Wardner Special for Toaplan MD ports of unconfirmed origin. Nobody seems to talk about Wardner Special much. Sure looks ugly as sin compared to the PCB, unlike Snow Bros, but I've not played enough of it to comment any further.
I love how there's a photo of Slap Fight's monstrous PCB in the MD version's manual - "look at this big ugly non-JAMMA m^$%*£er, I bet you're glad you've got this handy MD cart!" Yes indeed!