I haven't read anything about it yet (unless I missed something), and so that the team approving things looks into it and to make it gain notoriety for people that don't know about it, I submit the Lords of Battle datasheet book for approval.
http://www.box.net/shared/diel1ercmsWhile those approving it probably know about it, to people who haven't heard about it before...
Lords of Battle is a small book of datasheets (kind of like Apocalypse: Reload) that was put together by a small group of dedicated fans and tested relentlessly. From experience, I have found it to be very balanced and fair. In fact, it was the first to post rules for some things that Forge World came out with later (such as the Reaver titan) and Forge World's rules were much more powerful.
The Lords of Battle rules are a neat group of datasheets for many units found in Epic but not yet brought to 40k, along with other things that have only been discussed in fluff. You should check it out and see if it gives you any ideas, I know it sure gave me some.
Any datasheets that have since been made by Forge World or Games Workshop would of course supersede these, but the great majority still have not.