Well, the ones I like in the Top-Lane are as follows, in the order of most played to least played:
He's the kind of champ you can be really aggressive with, and based upon your comments on liking to bully and snowball, I think the Ol' Dunkmaster is right up your alley. But, a thing to keep in mind is while you CAN get some deadly traction going, you are NOT invincible. He has weaknesses, same as anyone else, and his most hated ones are Kiting, CC, Shields and Heals that can deny kills via his bleed in the event that his Dunk didn't do the job and probably a few others that I can't think of at the moment.
Yes, another Juggernaut. Yorick here can PUSH with his Ghouls and Maiden, and since you said you like to Push, he can fill the bill really well. But, his Ghouls and Maiden also represent a lot of his combat-power, so you don't want to be without them or at least without the option to summon them should you find yourself in a tight squeeze.
Noticing a pattern here? I Like Juggernauts. Garen's tried-and-true Spin-To-Win can clear waves AND kill enemies, thus allowing him to do the bullying and pushing you mention above in your post. Garen has what I call "Garen's Disease" which means, aside from Illaoi, I think, Garen is one of the MOST susceptible Juggernauts to Kiting, as the only real Gap closer aside from Flash is his Q, which cleanses slows, but does NOT make him immune to any more slows AFTER activation of his Q. So champs like Ashe or others that can apply a consistent slow are the stuff of Garen's Nightmares.
Now I'll get more into the Top-Laners I like that can become the impassible Brick Walls you mention in your post. Once again, in order of most played to least played.
If you're facing an auto-attack dependent champ in the Top-Lane (Like
,
, in certain cases
and maybe a few more I can't think of at the moment) Shen will REALLY ruin their day. The Taunt from E and Auto-attack block from W throws a wrench in their attack patterns quite a bit. Thing is, he takes a bit more awareness to be effective, as teammates will be expecting you to save them from enemies (Or in some cases, themselves if they go in too deep or get caught out), and landing (Or not landing) your Taunt makes or breaks you in the laning phase.
Q: I mainly use his Q when I know for sure I can charge it up to a reasonable level, because of all the ways he can be interrupted whilst charging it. Now this doesn't mean you should ALWAYS go for the maximum charge, because the enemy won't sit and wait that long unless they've been stunned or rooted.
W: Once you've got a point or two in his W, try to last-hit AMAP (As Much as Possible) to get that passive health increase. I mainly use the W in joint with his ult. I'll explain more when I get to his Ult. But, don't be afraid to use it if it can help you survive a gank or something like that. Also, remember that if the shield's still up after a short time, you can reactivate the W to damage units around you.
E: I use his E as a harassment skill more than anything. I don't use it unless there's a Minion I can send flying towards the champion I'm targeting. Remember, if the Minion that you send flying backwards hits a champion, it applies the damage and slow to them as well.
R: Try to make sure there's at least a small amount of terrain to travel before colliding (provided they don't have a Dash or Flash, to quickly get out of your way) with your intended target. When you begin the run, use the first active of his W, so that when you hopefully collide, you can reactivate it for the area-damage.
Your Harass is your Q, use W to stop dashing champs, Only E if you need to escape or you are sure they will collide with a wall and get stunned.
(Yeah, was lazy on the Poppy one.)
That's all I can come up with. (I'm a Top-Lane main) Good luck deciding what to main!