What I Did

I have made changes to Prisoner and am left with a slight dilemma. Here's the  new list:

4 Coalition Flag
3 Martial Law

4 Frost Raptor
4 Mistfolk
3 Blinding Angel
2 New Prahv Guildmage
4 Somnophore

3 Ponder
3 Supreme Verdict

4 Mana Leak
3 Dismantling Blow

9 Snow-Covered Island
9 Snow-Covered Plains
2 Flood Plain
3 Boreal Shelf

I am currently most dubious about New Prahv Guildmage. This is because I'm dubious about everything in this deck right now.

I went snooping through the Coldsnap block to see if there was anything that could help me. With 21 'Snow' lands, it seemed like it may be possible to find something beyond Frost Raptor to improve this deck. Rimefeather Owl was the closest I came. As much as I like a 7/7 flyer that can get bigger, I don't see it contributing to the deck enough to make it valuable. When you cast something for 7 mana, it should make a statement or cause your opponents to make one.

I took a long hard look at Kismet and it's blue brother, Frozen Aether, to see if they would fit but I'm just not feeling it. In conjunction with Detain, maybe but this deck has already demonstrated that one-time Detain effects are not helpful.

Having permanents ETB tapped and then Detaining for a turn? That could work out very nicely but it's a different deck--one I'm keeping on the back burner of my brain. Anything that annoying should be awesome.

So I'm thinking about something that might be a little more helpful: Faith's Fetters. It's expensive but it affects any permanent, including Planeswalkers and lands (I'm looking at you, Maze of Ith) and extends my game by at least one card, using Magic math that says: 2 life = 1 card. This could allow me to continue my soft lock and finish the game off; or at least, I hope so.