I gave up trying to maintain it as a small shrub. It tends to make long whips after pruning, and the wind (summer) breaks some, or the winter breaks them. Add to that the canker that seems to affect them, for myself it is easier to keep it to 4 trunks and let it grow. It is now about16 ft. tall, maybe 10 years old. The birds relish the bark as nest lining. And whaas, they never really "fill in". I can post a pic if that will help.

Pic, yes please!

The ones at the Chicago Botanical Gardens are fairly full (at least to my eyes). Perhaps I have to take a closer look to see if they are pruned or if they let em go.

I think this plant is quite variable in density and shape.

I hear what you're saying about the whips and canker though.

Have seen no problem with lack of density here, nor does shrub come across as one that is liable to be improved much by pruning. Only noticeable issue is lack of hot summer needed for fully expressed fruiting every year.

For some reason I can't import pics this morning. If somebody sees a red laptop flying through the air, please bury it when it lands.

Bboy, is the canker an issue where you are? What happens here is a canker forms on a straight stretch of branch. Then the plant sends up 3 shoots (they look like watersprouts on apple). The great majority of these break off, leaving bare trunk. I have 3 pics from yesterday, but I don't know how to post them, or even link all 3. I'll put a pic of the canker (after years of healing) in the link, the others will be cut and paste. Sorry.

This is the tree from a bit of a distance. Basically, the only thing with leaves is the Hep.
http://img.photobucket.com/albums/v280/AlbusAlbuseser/Plants/DSCF4933-1.jpg?t=1367264403

This is the form of the shrub, such that it is. As an aside, I would not plant another one of these even if it were given to me free. As long as it lives, it can stay, but even a so-so Viburnum is better than this.
http://img.photobucket.com/albums/v280/AlbusAlbuseser/Plants/DSCF4933-1.jpg?t=1367264403

Here is a link that might be useful: Heptacodium canker