Electromagnet help please

My team and I are in the process of designing a small steel-ball MagLev experiment whereby a high-permeability material steel ball is suspended in the air by means of an electromagnet pulling it upwards (from above). We'd like the system to be as small as possible and would like the ball to be in the range 7-10mm (or similar) in diameter with the cylindrical electromagnet core (without wire turns) having a slightly larger diameter and and a lenth of approximately 60 - 70mm.

If anyone knows where I can come across a supplier (in Europe, UK would be ideal) who has this that would be greatly appreciated.

regards,
gvanto