Just curious if the LED upgraded Maglite you have are the "D" size battery series or the Mini Maglite dbA line.
They do sell the cammed or cammless reflectors that can be had from Modamag and Fivemega. But with the current ones they have, you might first want to check to see if it'll fit with your "drop-in" LED. I have one in the MOP version (1st/2nd Gen) that fits well with my DB-3W on the 3 D Maglite. If in the Mini Maglite, then The Sandwich Shoppe sells the reflectors in the form of the McR-xx line.
The one that Cratz2 described above works fine also, but it'll take some "experimenting" to get the desired effect. I did that with mine to and am please with the "patterning" I arrived at.
Hope you find what you're looking for and Enjoy!