what a great idea!
heres a question. Does the model have to be the traditional sectioned globe, or could it be a complete cell with the various organelles deposited inside, and those that need to be in a specific position held in place by wire?
Don't forget, that once you are inside a eukaryotic cell things are not held rigidly in place, so you can be a little freer with the placement too i would presume. A eukariotic cell is defined as a cell containing a nucleus in addition to other organelles such as mitochondria ang Golgi bodies (who would have though that i would be using my GCSE biology for knitting, I love it!). It is only in text book diagrams that everything apears in such a rigid structure, the cells when viewed under a microscope are often much more disorganised and freely aranged (with a few exceptions of course such as red blood cells).
my first thought was somthing like this you see:
(WARNING!! NOT FOR THE EASILY OFFENDED)
A knitted globe (maybe slightly elongated)containing an assortment of organells which are comonly found in a eukariatic cell. If you are going to do a plant cell then i would do two knitted globes, one for the cell wall and one for the cell membrane and would try and make it a little more oblong, perhaps following a basic tote bag pattern to get the cornered effect. The organells could be created using stitched squares of stockinette. for example a mitochondria could be made by making a shallow bowl shape (again based on the bottom of a tote bag but scaled down) and then filled with folded squares of stockinette or garter stitch to represent the crista.
oh i just realised how long this post was ... i gues i got a little excited by the idea.