okay, i dont ever go above level 30, because all that happens is you and the monsters get more health, everything is fully leveled, etc.

anyway, onto the problem. i am level 30, and certain quests require you to sleep to continue. darkbrotherhood, mages guild, vampirism, etc.
is there any way to sleep or proceed without leveling? i am on 360 by the way, so no command codes for me.

I think you can afford to sleep its only one level. I do a similar system I level up to 30 and I don't go above it however I only use 4 majors like for example my current character she has Block, Light Armor, Alteration, and Restoration as her 4 main majors then I have 3 filler majors that I'll never use which is Hand to Hand, Marksman, and Speechcraft. Its a fun system although its a terrible system if you want to efficient level but that makes it more fun. Under my current system she will max her 4 majors around level 28 then I'll just waste a level and a half and get myself to 30.

I believe the only thing you can really do is trhis: Suppose all you want is to level till 26, coz this is the lowest level when you will see the highest leve enemy (a lich). When you reach level 26, you will do stuff that makes you skills go up. before leveling up, use command console 'setlevel 25' so your level appears as 25 and keep doing till you cannot level up. A horrible solution, but the system is horrible, so choose your horror....

I'm afraid that if you sleep you will level up.

I always 'cap' my characters max level by selecting several 'never use' majors, similar to what Terror described above.

Pdesbois' solution works too, but requires the PC command console, which you do not have.

Whta's wrong with utilizing the difficulty slider to compensate?

I have no doubt it works well for some, but not for how I want to play. I want all weapons and hits to be very dangerous. I want my character and all her foes to hit very hard, and take very serious damage if hit. The difficulty slider only makes one half of this equation possible. Capping my character's level at 20 and keeping her endurance at 30 works perfectly for me though.

If my character gets hit two or three times by a bandit I expect her to be dead. On the other hand, my archer is lethal with a bow. If she hits her target, I expect it to be dead within two or three arrows. I'm not interested in my character doing more damage while her foes do less (easy slider). Nor am I interested in her foes doing more damage while she does less (hard slider).

i am positive that if you contract vampirism PH, then sleep to become a vampire you WILL NOT level, just did this, did not level, just got the dream vision.

the OP states clearly he is on XBOX.