I play a ton of turboland and I am pressure sure I play about as much Parfait as anyone else right now. I have frequently considered a hybrid, but I have never actually bothered to seriously test one.
Here are a few comments and ideas to try.
First of all I can say with great confidence that by far the best unrestricted card in Parfait is Scroll Rack. I would probably run 8 if I were allowed to. It is so good that I have tried using Sensei's Diving Top as a poor man's Scroll Rack at times. I strongly suggest running a full set of Scroll Racks.
In general Order of Leitbur seems very week to me as does Meddling Mage. Seal of Cleansing is a strong card, but running four may be too many. Seal is fairly terrible against many decks including TPS and Dredge. Still, it is a strong card in the current meta and Null Rod is annoying for your deck so having answers to Null Rod, Oath, Time Vault, Painter and so many other threats is definitely good.
Some cards to consider:
Weathered Wayfarer:
Weathered Wayfarer is a 1cc beater who has the ability that you can pay

and tap him to find any land in your deck. You can only do this if you have fewer lands in play than your opponent, but you should already be doing this.
Once you add the turboland engine along with Mox Diamonds, Weathered Wayfarer becomes pretty good.
There are three great uses for Wayfarer. First you can find Strip Mine. In a deck with Fastbond and three Crucibles finding Strip Mine is huge.
Next you can find a fetchland. As long as you are running so many colors it is nice to have 1 Fetchland that could fetch out your off color Basics.
Third is Bazaar of Baghdad. Bazaar probably does not make sense, but it is a nice little draw engine with Land Tax since you can put three new basics into your hand each turn and then discard them to Bazaar to draw 2 new cards. I have tried Bazaar in Parfait in the past and it was fairly terrible at the time because between Mana Lands and Bazaars it is tough to have a Bazaar, enough mana sources and fewer lands than your opponent. I only mention Bazaar here because with Mox Diamond unrestricted it may be possible to operate with fewer mana sources in play.
Bazaar of Baghdad:
See above.
Aura of Silence:
This is sort of like a disenchant that is also highly annoying for Long, Drain Tendrils and Empty Slaver.
Argivian Find:
White, 1cc, instance speed Regrowth for Enchantments/Artifacst.
I frequently run this as a 4 of in both Turboland and Parfait. It really is amazing for getting back countered/Duressed Scroll Racks, Crucibles and Fastbonds. Also it recurs Tormod's Crypt against Dredge which is nice.
Ethersworn Canonist:
2/2 for {W}1
Says that any player who has already played a non-artifact spell this turn may not play another spell.
This would make a solid replacement for Meddling Mage since it hates out Storm decks very effectively.
Sensei's Divining Top:
This card is very good if you are shuffling each turn with Land Tax, Weathered Wayfarer or even recurring a fetchland with Crucible.
Nomad Stadium:
Land that produces

for 1 life or you can pay

tap it and sac it to gain 4 life.
There is an infinite combo with Crucible where you can gain infinite life with this card. In this manner it sort of simultaneously acts as a Plains and a Zuran Orb.
I am not sure if this would work well or not, but it is probably worth trying.
Orim's Chant + Abeyance:
These guys are solid against Yawg decks, but with Tezzeret and Painter all over the place perhaps they are worse.
Children of The Korliss:
Good sideboard card against Tendrils based decks.
Ray of Revelation:
As long as you are running White and Green this is pretty good against Oath and Dragon. It could make a decent sideboard card.
Wheel of Sun and Moon:
Solid sideboard card against Dredge although these days I generally run 4xCrypt, 4xPithing Needle, 4xChildren of Korliss and Moat to defeat Dredge post board.
Still I have not been running 4xMox Diamond. Having 4xMox Diamond makes this more of a turn 1 play which drastically improves its playability against Dredger.
Pithing Needle / Tormod's Crypt:
Needle is solid against Dredge, Welders, Tezzeret, Time Vault and Grindstone. Probably sideboard cards.
Tormod's Crypt just got worse, but it is still good against Dredge, Dragon and Yawgmoth's Will
Isochron Scepter:
This card is solid in Parfait if you run Orims and Abeyance, but I doubt it will work in your deck.
Moat/Humility/Ensaring Bridge:
I have run these in Turboland and Parfait, but these do not work if you keep your creatures.
In the past folks haved added Red to Parfait and used Lava Dart to drop down their land count so they can Land Tax. Also they have used Blood Moon or Magus of the Moon to get more red mana and randomly hose their opponents. Magus of the Moon sort of messes with any sort of Turboland combo, but it may be worth running.
You could for instance run a mostly Red deck with Red and Black splash. This allows Magus, Lava Dart, Tutors, and Condifant. You could run 1 Bloodstained Mire for Weathered wayfarer to find and then a Mountain and a Swamp.
I hope these ideas are helpful. Please post with your results if you test any of the out.