Hello people! I don't have a katana in my collection yet and if I get one, I would like it to be one of these styles - with double edged tip area, either curved or straight: http://www.ksky.ne.jp/~sumie99/Naohiro4.html
So if you have pictures of such nihontos, I would love to see them... Thanks in advance!

Well that specific geometry is something you see before the katana sword was made so they are seen in tachi style swords...not so much a katana. Although almost production swords of that style uses the katana fittings.

http://www.ksky.ne.jp/~sumie99/Naohiro12.html

These are nice blades! What period are they? Link I posted in my first post says that one such blade "was a treasure of the Taira family in 12th century". What kind of fittings would such a sword in that period have?

There are 3 such old blades. The most famous one is the one that gives its name to the style, Kogarasu Maru (which has its own Wikipedia page.

I don't know about the other 2 old blades, but the more recent ones are usually copies of these, or at least inspired by these.

In relatively recent times, this style has been used for swords for Japanese marshals/field marshals/gensui. Here is one example. The mounts of this are of an old style, possibly how the original Kogarasu Maru might have been mounted.

Bugei once did a version of the Little Crow. Here is its page, though I'm almost certain they've discontinued it.

http://www.bugei.com/littlecrow.html

EDIT: Upon second glance, that's a much older version of their website. They probably left it up for reference.

Well there is the Cold Steel version and one can get it for a lot less than on the Cold Steel site if one looks around a bit.

Certainly not something that would satisfy a Japanese sword purist looking for something close to an authentic Japanese sword, or how it would have been made, but good enough if one just want a sword to play with and enjoy the design.

http://www.coldsteel.com/japanimperial.html

From Kult of Athena:
http://www.kultofathena.com/product.asp?item=...dge+Katana

I have and early version bought around 2001 or 2002 but looking at the KoA pics the finish looks better and grind lines more precise, mine has a few visible grind marks and some small geometric imperfections.

The steel looks pretty good but since I'm not primarily a collector of Japanese swords I'm not that fussy about authentic details. ( Like I said it's still nice to handle and get a feel about how one might use it's partial double edge ).

Hanwei came out with one in their popular Raptor series as well, though the back edge isn't sharpened.