I was meandering through Jan D. Bastmeijer and found an informational page on a new species called Cryptocoryne yujii:
"Mr. Yuji Sasaki from the Rayon Vert Aquarium, Kumamoto, Japan, is a very successful collector of Cryptocoryne. In 2002 he found this species in Sarawak in the neighborhood of Sibu in several streams. This is quite amazing because this area is well investigated by several collectors.
Cryptocoryne yujii is named after its discoverer, Mr. Yuji Sasaki. The chromosome number 2n = 34. Comparing C. yujii with other species from Borneo, one might think of C. longicauda (2n = 30) and C. fusca or C. ferruginea (both 2n = 34). This species however is very distinct in the rugose spathe and the long, narrow kettle. The plant seems to be rather easy to cultivate, results both in Japan and the Netherlands are hopeful."
Judging by the page, this species is very easy to cultivate and probably does well in aquaria. On the site, there are several pictures of this plant growing in the middle of muddy rivers. The leaves remind me of Cryptocoryne pontederifolia.
Here is a link to some pictures of the plant and the beautiful white flowers: http://users.bart.nl/~crypts/Gallery/yuj/yuj.html