Colette Peters has a really pretty cake topper that is in the shape of a pineapple in her book on Weddings. It's a 3D version and all white.
I think I remember that pinapple post. You might be able to do it with the 3-D egg pan.
Oh, oh, I did one looong time ago. I wish my picture was bigger. I used the Easter Egg pan and did the three color tone to achieve the color on the pineapple. The three colors were brown, yellow and green. I covered the pinepaple with the big star tip to make it look spikey like the pineapple surface and then with the big leaf tip I did the top of the pineapple.
Well, I can post it. Its too big. I will try by email.
Here is a site I found that actually sells a pineallple cake pan.