So I got the chance to playtest this in an 8-way multiplayer game, and it did not end well. I started off with a Hive Mind in my hand, enough mana and a bunch of cantrips. Over the course of some turns I played some Truth or Tale and dug myself to some lands, a time reversal, a [[scrambleverse and a Stitch in Time.
Turn 6 I was able to drop the Hive Mind and pay 2 for Gitaxian Probe, which sort of set everyone thinking. It was fun, but took ages and people didn't get it quite well.
The Gitaxian Probe drew me another Gitaxian Probe and I passed the turn. The player next to me, featuring a pretty huge sliver army, had asked to look at my hand and saw what was going to happen (especially Scrambleverse wasn't his favourite) and attacked me, after playing a Harmonize, which drew me an Eye of the Storm, a Telling Time and a land.
Turn 7 I dropped my Eye of the Storm and payed 2, going to 11, for another Gitaxian Probe, them getting 2 and me getting 1, and everyone looking at everyone's hand. I was all set to play a land next turn and Scrambleverse, but after I passed the turn the Sliver player next to me said 'yeah, I really don't want this game to get THAT much more complicated. So I'll just attack you for 40-something' and that was it.
So what I feared came true; after my 'combo of crazy' hit the table, I became an insanely big target not because of board presence, but 'metagame presence' =D My opponents just didn't want to calculate and figure out stacks for hours everytime someone played an instant (something I would love ;) ) and got to me. Which is fair enough, by the way.
So still, this deck is hilarious. It features enough ways to dig for a 'perfect hand', you have time to put down enough lands and whatever you can play before turn 6 is just a bonus. I had my combo down, things would have gone smooth. I would only advise to play this with people who also love this kind of stuff, messing with the stack and figuring out all the little details ^^
I would make some adjustments tho, as I found 25 lands to be too much. I'm thinking of just adding some simple acceleration, and recently remembered Izzet Signet which would do a perfect job. The Vivid lands aren't really needed, cause you don't want to waste your Double Negative too early. (It's supposed to mess with a stack) so I'm thinking of removing them, and adding the last Izzet Boilerworks. I found it keeps my hand filled, and allows me to go down in lands a little. So I'd probably go 9 Island, 7 Mountain, 4 Izzet Boilerworks and 4 Izzet Signet, still having 24 mana sources (only going down 1) but a better way to shape my hand and mana pool. That opens up a slot for the last Truth or Tale ('cause it's more fun than Telling Time)
Also I removed a Swerve for a Redirect which I could trade, as it interacts better with Double Negative and things my opponents might play. I'm going to try and replace the other asap.
So that was it. New playtests will generate new posts, I'm still really psyched about this deck and it's a hell of a lot of fun. (oh, the looks on people's faces...) I just need to find the right playgroup and/or mindset to play it in. Preferably against a Zedruu the Greathearted *f-etch*, a Grouphug and a Death and Taxes deck. That would be awesome.
If anyone has actually gone and built this, btw, I am incredibly honoured, and I would love to hear about your playtests!