Well, well... What do you know, I spoke too soon!
Managed to find Mark Mullins' Allocate Hits Rules at this page:
http://www.scribd.com/doc/28224177/Epic ... Hits-Rules 3 pages, (really 2, but one is a duplicate. 1 page rules, 1 example.)
Uploaded quite recently too, prolly why I managed to miss them the first time around.
The gist of the new rules seem to be the prevent a player rolling only a few dice from picking off weaker units way back, since you *have to* allocate dice to each unit starting with the closest. So if there are 3 Leman Russes in front of a bunch of Guardsmen, and you roll 3 dice to hit, then you *cannot* hit the guardsmen since you have to allocate your dice to the Lemans first!
When rolling buckets of dice, I'm not so sure it makes any difference. All in all, seems like a good addition to the game. Sure makes infantry a tad more likely to survive outside cover.
There is also some other stuff there, such as rules for Imperial Moles (Official) and for Whirlwind Flak (Rejected). Be sure to click around for a bit, the page isn't all that user-friendly. The other stuff is either in the Battles Book or already included in the link.
I shall update the rapid-share link too when I get around to it.
Edit: Make sure to read the example too, I got stuff wrong from just reading the rules... Any dice which cannot hit *any* models in the target detachment are discarded outright and so cannot be allocated. Perhaps obvious to the rest of you, but to me it was quite illuminating.