Got rid of all the fat and lowered my card count to 40, which is apparently allowed on this challenge, and finally beat it.  The end result is very similar to aww1979's "Boring Angel" deck, except with some Phyrexian Walkers and no Preordain's.  
The lone Mirror Universe actually saved me in the round where the comp starts with two Ivory Towers, since I was dealt Blightsteel Colossus in my hand, got my Show and Tell countered, got out my Platinum Angel but couldn't deal more damage than the Towers healed.  Good thing I quickly only had 1 health and eventually picked up my Mirror Universe 

  That was the only round I actually needed my Platinum Angel - "Boring Blightsteel" would be a more appropriate name for this deck, since that's how I won 9 out of 10 rounds.  
Anyway, with a stripped down, Mox'ed up deck like this the challenge only took two or three tries, since with decent luck you can get out a tutor for Tinker on your first turn on round 10, and get out your Colossus on turn 2 for the win.  
.126	11	Island
.1351	1	Tinker
.782	1	Blightsteel Colossus
.1308	1	Platinum Angel
.169	1	Mox Sapphire
.230	1	Sol Ring
.334	4	Personal Tutor
.17	1	Black Lotus
.312	1	Ponder
.249	1	Time Walk
.1	1	Ancestral Recall
.1758	1	Show and Tell
.1317	2	Phyrexian Walker
.725	1	Mirror Universe
.173	1	Nevinyrral's Disk
.165	1	Mox Emerald
.166	1	Mox Jet
.167	1	Mox Pearl
.352	1	Mystical Tutor
.168	1	Mox Ruby
.499	1	Brainstorm
.1891	4	Echoing Truth
.894	1	Mana Crypt