The stat build is easy to pull off and still have a very solid character. See my example below.
It'd be a feat; having to point-buy 18 WIS with an Eladrin would kill any chance of having the right stats to do the trick properly. The cost of the paragon path is definitely too high though, I agree. HOWEVER, as shown before there is an orb item that lets you make the save auto-fail, and technically that's the only item bonus you need to absolutely guarantee the unconscious effect once Sleep lands.
Could you explain that one to me? Also, that item is really just to enable making a saving throw "unsavable" earlier, it's not actually necessary for the build.
Again, see example lv1 WIS below for the stat spread of a solid Wiz that can also pull this combo off.
The sacrifices really aren't that great. You can technically pull the effect off with zero item enhancements, they only help ensure it works. Probably the only key item would be the Orb of Karmic Resonance which will ensure the target fails the first saving throw. As far as making the attack land... well, getting a bunch of to hit bonuses is easy, just see the party leader

Powers like Warlord's Favor, a level 1 encounter ability (and we're talking about doing this trick late paragon with item help or lv28+ without...), can add a big chunk to attack bonuses, on top of tactical presence and combat advantage, wand implement bonus if you have the feat for two implements, AND elven accuracy if all of that fails... it's really not too tough to make the to hit land.
Here's the example build I kept mentioning that makes for a very solid orb wizard that also has zero problems utilizing this trick without making any sacrifices:
====== Created Using Wizards of the Coast DDI Character Builder ======
HAZROR, level 1
Elf, Wizard
Arcane Implement Mastery: Orb of Imposition
FINAL ABILITY SCORES
Str 8, Con 10, Dex 14, Int 16, Wis 18, Cha 12.
Starting Ability Scores
Str 8, Con 10, Dex 12, Int 16, Wis 16, Cha 12.
AC: 13 Fort: 10 Reflex: 13 Will: 16
HP: 20 Surges: 6 Surge Value: 5
TRAINED SKILLS
Arcana, Nature, Insight, History.
FEATS
1: Ritual Caster
1: Improved Initiative
POWERS
1, At-Will: Thunderwave
1, At-Will: Ray of Frost
1, Encounter: Icy Terrain
1, Daily: Sleep
Spellbook: Flaming Sphere
ITEMS
Spellbook, Adventurer's Kit, Cloth Armor (Basic Clothing), Arcane Implement, Orb, Dagger, Longbow, Arrows (60), Alchemical reagents (Arcana) (20), Tenser's Floating Disk, Comprehend Language, Animal Messenger, Rare Herbs (Nature) (10)
====== Created Using Wizards of the Coast DDI Character Builder ======
Certainly needs Toughness and Armor Proficiency (Leather), but it makes for a very solid build. Elf race enables a lot of mobility w/7 square movement, and the ability to shift through difficult terrain is definitely useful for avoiding opportunity attacks as a wiz that you'd otherwise be stuck taking. Elven accuracy helps a lot for ensuring those important control effects hit. +2 perception and +2 nature go great with the stats you'll have; hell, with such high WIS, you may as well take Skill Training (Perception) and if you added skill focus onto that you could have 25 passive perception at level 2 for overkill purposes... Basically the point I'm making is Elf is a GREAT race for an orb wizard, though it might not seem like it at first glance. He has enough stat-wise to qualify for any feats you'd want (except I guess Solid Sound); that +2 dex really pulls through in that department, enabling arcane reach, evasion, etc while still having enough stats for Spell Focus. The truly patient could even go 15 DEX 11 CHA and hold off on spell focus until epic tier if they wanted a DEX 17 feat like Seize the Moment or Defensive Advantage, but I didn't want to wait an extra 10 levels with that character just for access to a feat or two. Basically, the stat spread isn't a problem.