HorvatM has released InsmEdit, an Insmouse No Yakata editor for Windows. It can currently edit level layouts, passwords, and player starting positions. Grab and discuss it here.

In addition, Ben Stevens has released a guide for Insmouse with 100% correct level maps, in contrast to earlier guides.

Attachments:

1. 

   insmedit.png
   

Good work fella, mucho grande kudos to you.
This could, like you say, lead to a whole new PVB related ROM with levels by us.
I do hope you manage to sort the monster placement editor too.