Larzuk's Sockets.

[Crystalion]

The ilvl thing needs more explaining, I think.
...
Now, on to the Larzuk socketing...

It should perhaps be mentioned, since so many people are following the v1.10 beta, that another thread discussed the mechanics of the socketing ("white" item) cube recipes, and they seem to roll a 1..6 random, and *then* cap to the max allowable for an item. This means they might be your best bet to get what you want in some cases in which Larzuk is unlikely (or can't) come through for you.