I've only read about the last 1/2 the posts here so forgive my ignorance, but a couple of comments:
Neat mod. The grappling hook armo(u)r sounds like lots of fun, as does the vine-man walking on walls. I like the idea of a vine or vine weave as the liquid transport. Even cooler if they were OPAQUE and you couldn't see the fluid in them, but they would drip like water and lava do now through dirt and stone with the liquid they are carrying. Vine not being the best building material.
Also, consider several tiers of objects for creation. Since this is being developed over the FTB forums, consider that it will most likely be distributed with other mods. MFR seriously destroys any limiting based on the number of vines you have. 10 mins of game time with a jungle tree harvester will fill a double chest with vines. I constructed my first void pipe to combat the sheer number of vines I had coming into my system. So other than early game items, reliance should be on vines that have been process in some way: dried, soaked in water, run through your pressing machine, something.
Also, you open the possibility to cultivate vines with different colored blooms on them to decorate one's home. I hope something like that could make it in. Entirely non-functional but awesome looking designs on castle walls that GREW there.
Hopefully I didn't bring up any long-ago discussed items.
