How to force menus to appear in two lines: in first line mvc musicstore control menu right aligned and in second line this css3 menu? Should I add <table> with two rows to Site.Master or is there better solution ?  

if you want the menus Items of the two rows be aligned on a common column you have yo use a table otherwise it is enough to put the two menus within two divs and then styling the divs adequately to your needs(fixed width or self-adapting to the width of the page, or to the width of the content.

Can your treeview styled like horizontal menu ?

Pay attenttion! Also in the CSS menus the only thing organized orizzontally is THE FIRST LEVEL OF ITEMS, the items below the first level open vertically(from above to below). Therefor the point is only organizing the first level orizontally...yes my tree can be organized this way...you can achieve this also with the tree you are already using with an adequate styling. For instance, the css instruction that makes the first level of the menu appear horizzontally is:

#nav li {
	margin: 0 5px;
	padding: 0 0 8px;
	float: left;
	position: relative;
	list-style: none;
}

the float: left force the <li> to be stacked one after the other from left to right. This would apply to all <li>...but this is not what we want, ...the level after the first be organized vertically...so another css instruction is provided:

#nav ul li {
	float: none;
	margin: 0;
	padding: 0;
}

This instruction override the float: left with a float: none for all items below the first level.

Where to fidn your treeview demo ?

I just finished developing it. Now my tree is under test. It should be released next week together with the new 0.9 release of my Mvc Controls Toolkit.

Pls go here: http://mvccontrolstoolkit.codeplex.com/ and subscribe to be notified for new releases (You will need to register...but it is easy ...just email username and password ). Subscribe as a follower of the project (about the top right corner) and you will be notified of changes.

Once the the new version will be released, you will find there, link of documentation, tutorials and code samples to download.

What is interestin is that the tree can be displayed in edit mode(for instance into an administrative page), and it will allow you edit your items, by adding new items, modify them, and moving them as children of other items(just by dragging them with the mouse). Once the View will be posted the .Net data structure that is behind the tree will be updated accordingly...so you can store everything in a DB.