Brainstorming Scratchbuilt Nids

As I get further and further into the planning for this Nid project, the more I think I might need a notebook for all my little thoughts.
Today I've been thinking about the ability to scratchbuild/kitbash some of the more annoying-to-buy models. Little stuff like spore mines and rippers. These are little add-on models that are used in units that almost nobody fields, but they run upwards of $1.50 USD per model? That's insanity!
As a result, I'm thinking of ways to simply scratchbuild them using Greenstuff and Nid bitz.

Spore mines are easy. Use the little extra detail bitz that come in almost every kit, and either add them to a small ball of Greenstuff, or glue them to a small brick of sprue, and use GS to seal up the blank areas, like putting crust on a pie or a skin graft on a burn victim, or maybe leather on a rugby ball? All of this mounted on a length of paperclip or brass rod, or even another length of sprue, which is then attached to a base. Use long ropes of GS to make progressive layers of tentacles drifting down from the "ball" and concealing the rod/sprue. Simple enough, and will likely look pretty good. Add small details to the skin of the mine, and done.
I'm also looking at Gaunt spinefists for this purpose. They have some nice detail, and with proper cutting, I think I can put a couple at an angle on a piece of sprue, and make a double-mohawk-looking spore mine.

As for Rippers, I've been looking at either Warrior faces or Gaunt heads. The Warrior faces will probably work best. Start with a face, remove the flesh hook tongue if it has one. Crown the head with a Genestealer armor plate. Slice off a Carnifex tongue from the long-tongued head and use it as a base for adding overlapping plates to the body until you can join it to the head. Fill any body gaps with GS, and add small textures like pores or what have you with some tools. Then, cut the thumb claws off of several spinefist bits and Gaunt arms, and arrange them in order from large to small. Add small knobs of GS as needed to form joints, and then press matching sockets into the GS. Apply legs to body, and body to base (probably with thin paperclip wire painted black), repeat 3-5 times.

I'm also thinking making Ymgarl Genestealers is stupid easy when you just cut off their lower jaw and apply a couple rows of tentacles.

Those are my ideas for now. I found a tutorial on making kitbashed Zoanthropes someplace, but can't find where I stashed the link...