I love awkward shy lead male characters that blush or nosebleed all the time. 🙂 Any suggestions would be greatly appreciated. Thank you. 🙂
yaoi or shounen ai are accepted

Beauty is so fleeting...enjoy it while you can.

The guy in Magico (IWAMOTO Naoki) is one, such a cutie. I know some more, but I will update if I remember...

Edit: Wait, I know the following may not be your exact shy/awkward guy, but they're still cute: Kawaii Oresama would be in your ally (the blushing bit), as well as Kemono ni Botsuraku Ojousama. It's so damn cute that it will make you squeal (if you into that type of thing 😛 ).

I also find the second guy in Tonari no Atashi, to be like that, although he isn't the main character, but:

she ends up with him, yay! Not the indecisive idiot, whom usually the girl ends up with.

I find that the guys in Moe Kare!! are like that as well, in fact many of the guys in this mangaka's series are pretty much blushy.

I'm in idol hell T.T

When it has to be the main character I can only think of Cyboy (Even if this one might not exactly be a match, because the character tends to hide this side of him) and a oneshot included in Gokujou no Yoru wo Ageru. ^^"

But - Aside from this, there was a few days ago a topic, which should be pretty interesting for you:

-> Blushy guy

"It's like love is a bonus in your life. Even without it, I'm just fine. I don't feel like pointlessly searching for it. You don't have to make yourself unhappy." (Ookami Shoujo to Kuro Ouji)

"Why does it rain?" - "To create drama." (Drops (Andou Yuki))

Koisome Momiji

This is a yaoi one (just a warning, I know you said that it's fine, but I didn't want you to read it and be all "Oh it's yaoi not shoujo/josei." I know that I hate it when I accidentally get the genre mixed up, so I thought I'd just warn you a bit). The first story has the shy/awkward boy. The second story doesn't have that type of character. Kimi wa Amai Amai
That's really the only one that comes to mind at the moment, but I'll update my post if I think of any others ^_^

[img]http://www.nodiatis.com/pub/23.jpg[/img]

Yeah the reason i made this post is because i fell for Shion from Magico. I want more characters like him. ^_^

Beauty is so fleeting...enjoy it while you can.

Try
[m]Seishun Otome Banchou

Well, the main character from Ookiku Furikabutte blushes all the time and is incredibly awkward (though I wouldn't call him "shy": it's more like he has low self esteem), but I dunno whether the mood of the series will fit your tastes. It's seinen and sports (baseball), with a strong emphasis on the game and team dynamics and not, say, romance or daily life.

There's a hell of a lot of blushing from both sides in Oka no Ue no Rakuen.

One of the leads in Flat (AOGIRI Natsu) is shy, awkward, and blushy, but he's just a little kid -- I think about 6 or 7. The other male lead is 16 and awkward in his own way, but not even remotely shy and never blushes.

Planetary* -- Awkward, shy, low self esteem. Doesn't blush that much, though.

Bagjwi Sayug, Ore no Shiranai Murakami-kun., Sabita Yoru Demo Koi wa Sasayaku -- Going by the first chapters, with confirmation from the category tags. I haven't read far enough to be absolutely certain, though.

And the Blushing Male Lead, Shy Male Lead, Awkward Male Lead categories should have some good titles, too.