Congratulations on your build.
Very well researched and executed - separated brake/shifter = saving of at least 100+ g over a SuperRecord, integrated seat post/saddle and stem/handlebar etc even a little "game cheat" - your <120g Tufo elites (more of a track tubbie and I am sure there will be many flames coming this way for the choice, but what the heck, this is a true ww build).
What else to cut weight? Very marginal at your already very ww build and may tend towards "surgical and cosmetic solutions" - tape till just the bend of the drops, saw off any excess from the skyline skewers, removing the wheel decals (itself at least -5g). You didn't mention about steerer tube top cap and spacers but I think you are using the tuned ones already. Really talking about a few grams here and there, tops 20g off or so.
The big difference is therefore your wheel set - they seem heavier than earlier Extralite builds (including mine) that have been mentioned in this forum of circa 780-790g stock from Extralite. These were built using the first version of Edge 1.24 rims, Sapim CX Ray spokes and extralite ultrahubs. Extralite used to sell them as the "HyperClimb moon climbers".
Some have tuned this original Extralite build to M5 front hub and Pillar Ti spokes to achieve 715 to 720g http://www.cyclingtechblog.com/2009/03/03/new-lightest-wheels-in-the-world-715-grams/
. This was back in 2009. Now there are options of AX SRT24 rim and lighter Dash hubs.
Based on the reported weight, your version seems to be the version 2 strengthened ones (Edge/ ENVE 1.25). So, depending on your weight (I am 70kg and have no problems with my Extralite Edge 1.24 build which I have owned for 2 years), you may want to source for the lighter earlier 1.24 version Edge rims, rebuild using Pillar Ti spokes and perhaps even lighter hubs such as DASH. This could cut more than 100g off to be closer to your target. Be warned though that spoke breakages have been reported for the Pillar Ti spokes http://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=97206
. So you may want to custom build CX Ray for drive side rear and use Pillar for the rest.
Happy experimenting. BTW, can you give us a summary of how you got about getting the integrated post-saddle and stem-bar from AX?
Current Bikes: Storck F0.6 6kg
, Storck Aero2 7.04kgStorck Organic Light 11.1kg
, Storck F0.7IS Di2 4.8kg