Maybe you shall add "sponges" to shop, they maybe bloc the lava or like 30 seconds at a range of a few blocks.
Wouldnt be bad to add a description to the shop - items
For example: Hammer - 20 [money] - Acts like cuboid. Type /hammer to use.
Oh and maybe this doesnt fit here, but is there a compiled versio ofthe "buy rank" command? i need it D: Or maybe you can add that to the shop too, and if you dont want it - disable it!
I got alotta ideas, but i think that's nearly impossible
PS : Dzienny, you are the greatest developer ever! Like 2 Updates a day! <3