I've started on a new account (a Khajiit Assassin)... I use bows primarily and I know one of the most useful enhancements is Paralyze, for obvious reasons. But over hundreds of hours of play (over several accounts, most notably my level 48) I have NEVER come across this enhancement. I always check shops, I loot nearly every chest, and I've gone through so many dungeons. I was wondering if there is maybe a quest reward with the enhancement so I can get it fairly quickly? Thanks.

Have you done all the citie's thane quests? I just finished one for Elisef in Solitude, you are given a leveled sword, Blade of Haafinger. This character was level 45, much later than my other 2, and the sword had the paralyze enchantment. Also bought a glass sword with paralyze at Warmaidens, level 32. Other 2 characters found similar in the mid 30s levels, in shops.

Isn't paralyze a skill from bow (Power Shot or some such)? I don't think there's a weapon with Paralyze as enchantment?

Paralyze and slow are potentially the 2 strongest weapons enhancements, and as such, they have the lowest probability of showing up. Waterbreathing is similar on the armor side.

Well those enchantments are random and leveled.

Paralyze is a high level spell, so you're probably just not high level enough for it to be showing up in shops yet. I'm not sure, but it also might be based on your skill with that spell school.

i have only come across paralyze once or twice in about 20 characters.

Poisons!

http://www.uesp.net/wiki/Skyrim:Paralyze

I must be one lucky SOB I have paralyze one at least 4 of my active characters my lowest being lvl 12, it was on a dagger in the chest in BFB.

i got a weapon with it and i disenchanted it, if you just make your rounds to the different merchants you find all that, same with muffle boots, if the merhcnat doesn't have em, just wait a few days and make your rounds again...you might need to be a certain level and skill level before you find certain enchantments.

what the hell, slow is a weapon enchantment?! ive never even heard of that.

paralyze may occur more commonly at lower levels (20-40). i dont know why but at very high levels certain mods such as muffling become absurdly rare.
paralyze is also potentially gamebreaking if you have a way to recharge it.

Like a Skyforge Battleaxe with paralyse and soul syphon on it you mean.
Two shotting Giants while they lie on the floor defensless is pretty much fun, the paralyse deosn't seem to be on a high chance of happening though.