scottysjo

Lookin at you here, vaevictis, Brion stoutarm, and Rhys

Yeah, monument is extremely good, but our group uses a lot of targeted sacrifice and exiles for cleanup effects. The hexproof works a little better for our local meta (no infinite combos and minimal infect in the deck also follows meta, for example) I really should try to find room for both though.

I ended up cutting Winds for the marshal's Anthem and the owl keeper in favor of trying to play more control style. Having to tap down mana for the upkeep makes people not fear the counterspell as much.

Champion of lambholt, Twilight drover, and spawnwrithe are all fun times in Rhys. Also consider Mimic Vat, seance, and akroma's memorial.

I made this with stuff I mostly had layin' around. I might try to squeeze an all is dust and an oblivion stone in it later, if it proves fun enough to play to justify the expense. I doubt I'll spring for a damnation though, they're up to $50 now and I'm using all of mine in other commander decks.

Sun Quan would be a good choice for slipping your guys past, as an alternative to all the shadow. Also, Quietus spike is fun times with wound reflection. Looks interesting with all the unblockable though, perhaps a little more ninjas to capitalize (Ink-eyes is a personal favorite)? I know you use Sygg for card draw, but what about the bident of Thassa/ coastal piracy? Also, Vela the night-clad might work better to help force your way though over Sygg.

Fatal Frenzy maybe? Fun times with your assault strobe... And trample. Yumyum.

You know I tried it and didn't like it much. It just doesn't do much for you without the tap-to-mill merfolk. I replaced it with the phrexian metamorph, he almost always has some kind of tasty target out there to copy.

Right then, a few things to change:
Your land base is a bit low. I try to keep at least 38 cards. You're missing some of the staple lands too, a few things to aim for:
Homeward path, Boseiju who shelters all, command tower, Shivan reef, scalding tarn (Expensive!), cascade bluffs, strip mine, tolaria west, terrain generator.
Your deck seems to have a variety of themes to it and could use a bit more focus. You seem to be about the copy effects more-so than not, so I'll aim for that. A few nice cards to aim for then:
Nin, the pain artist: She can draw you a lot of card and with your doubling effects can provide superior draw. She's also a wizard to fit your sub-theme.
Psychosis Crawler: He can take the place of Niv-Mizzet for your draw effects to kill everyone.
Diluvian Primordial: He's a much better source of enemy instants and sorceries than spelltwine.
Melek, Izzet Paragon: He can open up the top of your deck to play cards from there, and give you doubles. Fun on a bun if you roll Dream Halls too.
Uyo, Silent Prophet: Uyo is bombtastic. Sure she bounces lands but she wins games when she does.
Seismic assault: You'll draw a lot of lands with not much chance to use them. Why not throw them at people? Include a crucible of worlds and it's pretty powerhouse, even Uyo's drawback becomes a source of ammo.
Wild Ricochet, twincast, reverberate, fork: You roll the copy effect already but instant speed ones they can't see on the board can snag you some tasty buttons.
Cyclonic rift, wash out, evacuation: Mass bounce buttons can save your bacon.
Mind over Matter: If you have a fist full of cards or use a lot of draw effects it's a powerful table control mechanic.
Mirari: An awesome artifact for any sorcery or instant heavy deck.
Ophidian eye: It's curiosity with flash.

Here is a link to my red/blue Melek burn deck: http://www.mtgvault.com/scottysjo/decks/melek-burn/ for some other tasty combos and cards to look for.

Are you looking for input on the deck? I play a lot of commander and could offer some help.

Try to cut the colors down to two, maybe three. My sliver deck uses green and blue: Green slivers have all the pump and abilities, blue have lots of utility skills, and the clones galore. When you split to five colors you need a huge mana base that makes your land pool cost more than your car.

My deck is more control than yours, but I built it to abuse the quick sliver/ alchemist refuge. I posted it here if you'd like to see: http://www.mtgvault.com/scottysjo/decks/bluegreen-sliver-commander/

Change the sideboard to have answers to layline of sanc. or you lose? Chain of vapor maybe?

He listed his version of the deck on this site too: http://www.mtgvault.com/gladiatorw07f/decks/arcbound-riots/