LEADING DIAGONAL DISCUSSION:
I have tossed aside the [i]-[ii], (i)-(ii) count for a simple reason that it doesn't look right in that this subwave (ii) of [iii] is a larger correction than the next higher [ii]. This is particularly true if we have higher prices tomorrow.
With that in mind, lets explore the Leading Diagonal count and I'll post rules and guidelines per "Elliott Wave Principle, Key to Market Behavior" (Frost/Prechter):
Pg 40 of EWP (in my copy anyway) discusses leading diagonals: "....leading diagonal can take an expanding shape. This form appears to occur primarily at the start of declines [Daneric: their emphasis, not mine] in the stock market."
LEADING DIAGONAL RULES:
* A Leading Diagonal always appears as wave 1 of an impulse....
I am postulating that Minor 1 of Intermediate (1) of Primary  down is a leading diagonal of a much larger impulse pattern.
* Waves 2 and 4 of a leading diagonal always subdivide into zigzags
STATUS: Rule satisfied in this case.
Is it not curious how wave (c) of Minute [ii] just had to finish higher at 1332.28 above wave (a) of [ii]? Why did the market strain for this? Because it was a zigzag pattern and by rule, zigzags in all but the rarest cases I suppose, the (c) wave was required to finish above the (a) wave. And thus it did.
PROJECTION: I have projected that Minute [iv] would be a double zigzag pattern since it could not satisfy price requirements with one zigzag pattern, it would have doubled its form to attain price. This would satisfy the ZZ requirement for [iv].
* Wave 4 always ends in the price territory of wave 1
STATUS: Rule satisfied in this case.
* Going forward in time, a line connecting the ends of wave 2 and 4 diverges (in an expanding diagonal) from a line connecting the ends of wave 1 and 3
STATUS: This rule will be satisfied if we get higher highs tomorrow to the 1304-1316 price window for Minute [iv].
* In an expanding variety, wave 3 is always longer than wave 1, wave 4 is always longer than wave 2, and wave 5 is always longer than wave 3.
STATUS: This rule is satisfied so far in that [iii] is longer than [i] and [iv] is longer than [ii].
PROJECTION: Since wave [iii] is 83.23 SPX points long, wave [v] should at least be 84 points long. Therefore if wave [iv] ended at say, 1313, subtract at least 84 SPX points you get a minimum target of 1229 SPX for Minute [v].
LEADING DIAGONAL GUIDELINES
* Wave 2 and 4 usually retrace .66 to .81 of the proceding wave.
STATUS: Wave [ii] retraced 76% of wave [i] which satisfies the guideline. Wave [iv] should retrace 66-81% of wave [iii]. This target range is 1303.98 - 1316.47 to be precise.
*Waves 1, 3, and 5 of a leading diagonal usually subdivide into zigzags but sometimes appear as impulses.
STATUS: The current ambiguity and difficulty of the decline of [i] and [iii] to form a coherent subwave count satisfies this guideline in that it has a "hybrid" look about it - part impulsive-looking, part corrective-looking.
* Within an impulse, if wave 1 is a diagonal, wave 3 is likely to be extended.
PROJECTION: If this is a leading diagonal decline Minor 1, Minor 3 - sometime down the road a few weeks or month(s), is likely to be a very sharp and deep decline.
* In an expanding variety, wave 5 usually ends slightly before reaching a line that connects waves 1 and 3.
PROJECTION: You can see if wave [v] were to decline at a rate suggested in my SPX 30 minute chart, this guideline would be satisfied https://lh3.googleusercontent.com/-rE-WKKszwBs/TYfDwI1fZ1I/AAAAAAAAI6Q/V2ZpTWFNfTo/s1600/spx30.png It would come close to the [i] - [iii] line but fall short of it.
Obviously the rules and guidelines of a leading diagonal are fairly specific. So the end result is if the market does not behave as outlined in the discussion above we can simply toss this count aside.
[Update 5:33PM: I updated the 30 minute SPX chart below https://lh3.googleusercontent.com/-rE-WKKszwBs/TYfDwI1fZ1I/AAAAAAAAI6Q/V2ZpTWFNfTo/s1600/spx30.png with a precise target box for Minute [iv]. Prices derived from 66-81% retrace of Minute [iii] as per EWP. Target for Minor 1 low could still be the 2010 high of about 1219 SPX if Minute [v] is longer than [iii] which you might expect in a expanding diagonal pattern . Of course only a new low under 1249 is required.
PRIMARY COUNT is that the US markets is tracing a leading diagonal Minor wave 1 down and working on Minute [iv] wave. The leading diagonal should probably take an expanding shape.
Not only is the US markets merely a three wave down at the moment but so are most major world markets.
Europe's markets and Japan (and others) all require another wave to a new low to complete an initial 5 wave impulse lower. All of Europe's markets and particularly Japan had robust wave [iii]'s down but now require wave [v]'s. The US market is overlapping obviously.
So the #1 reason I am not buying the Minor 5 to new highs scenario is that if Europe's markets and Japan experience a wave [v] of Minor 1 down then the US is likely to align with that same downturn and experience its own new low which is required of a leading diagonal count.
LEADING DIAGONAL COUNT
According to EWP, each corrective leg of a leading diagonal should correct the preceding wave by .66 to .81 percent. Therefore we can expect Minute [iv] to hit a retrace target range of 1304 - 1317 calculating from the Minute [ii] peak of 1332.
SQUIGGLING A POTENTIAL MINUTE [IV]
A final wave of a double ZZ would place it into the target range of 1304-1316.
DRAWBACKSI postulated this LD count last year and discussed it in depth. It did not pan out obviously. The "marker" for this pattern currently is above the .81% retrace or about 1318. If it traces higher than 1318, the LD count is probably bunk here too.
The big difference is that last year's LD count was more of a contracting or "falling wedge". This would likely be expanding in shape which is more of an expected wave shape as a beginning wave off a major high.