What's special about the product that you're looking for. It may be that you're looking to include a configurable/composite product in your bundle which isn't possible. You can only include simple products in a bundle in Magento out of the box. To create the illusion of a bundle product, you'll need to replicate all of the configurable options within the bundle product by including all of the possible simple products that you may need.
----
If you've found one of my answers useful, please give "Kudos" or "Accept as Solution" as appropriate. Thanks!
