Firstly I, with any set I pick, will aim to be over the haste soft cap of 856, as while cf is a perfectly good talent, I like to pvp and in all honesty just have more freedom to move 7 points around in the restoration tree (assuming i drop natures focus) as it is frankly more interesting and allows me to alter my play style more to fit my style of play.
I currently am aiming to pick up 4xT10 which leaves me with the challenge as to chose which pieces to pick up within the set. The legs and gloves are both mandatory as I need the haste, which leaves me with choosing between helm, shoulders and chest. In all honesty I don't know which pieces are better itemized out of the three, but the shoulders have a smaller stat contribution, which in turn means a small loss of haste - but to cut a long debate short i'll take shoulders and helm because in all honesty I do love the looks of our new tier.
This leaves me with options on the rest of my gear. Now there is one thing you should understand about my gearing, I don't like picking up mp5 over spirit and the reason why is not the relative regen merits of the two, it is simply that all things being equal you can reach a higher maximum spell power with spirit on your gear, rather than mp5.
By totaling up my gear (I am working with 264 item levels as though I may be fortunate enough to get heroic kills I am not going to rely on getting 277 items to ensure I reach the haste cap). By looking at the rest of my gear it becomes apparent that you can reach the 856 haste soft cap so long as every piece has haste, bar one slot (not including trinkets).
When looking over my gear there are two particular slots that appear to require the most thinking about. Feet and weapon slot. I traditionally have always aimed for a main hand off hand combo as it has always seemed to have the highest overall spell power.
Sundial of the Eternal Dusk + Trauma
with possibly heroic/normal versions of Mag'hari Chieftan's Staff along the way.
Now feet slot is the slot that most frustrates me, don't ask me why but I always like stacking a bit of regen which means that I really don't like to take items that have crit and haste on them rather than spirit/haste. For feet there really aren't many options, with the only haste/spirit boots being the crafted Blessed Cenarion Boots. This leaves me with the conundrum either shell out a good 12k gold on the boots, or simply live with using a staff.
As always in the end I don't like using BIS sets, but more a priority system and I hope my reasoning above has helped you in some way, as gearing for the 856 haste softcap seems to be achievable, but requires giving up more than I had initially planned for.
ps. one of the main reasons why I am looking at Trauma is due to the relative high benefit druids get from the staff relative to other healers. If you would like further discussion about this feel free to consult the EJ druid itemization forum thread.