>Any more Sonoda stuff worth checking out?
Nah, just the manga of GSC and Bean Bandit the 7 minute kick started anime where only around 4 minutes is actually animated and the last 3 are credits. A shame too since it's exactly what I wanted from a modern Riding Bean.
I know a lot of people dislike the manga for certain reasons, the ending of Burst is kind of stupid and unrealistic but overall I enjoyed what I read just because it's fun in general. I also enjoyed the insights into guns from Sonoda, guy knows his stuff despite living in Japan.
I'd say if you enjoyed something like GSC/Riding Bean, here are a few other things I enjoyed that had a similar vibe, both retro and not:
Read or Die
Armor Hunter Mellowlink (also kinda, more mecha)
Candy and Cigarettes (manga)
Black Magic M-66
Dominion Tank Police
Urasekai Picnic (not that great though)
Not sure if they'd give you a similar vibe, anon. But hopefully you can scratch that itch with stuff here.