There are only a few high quality brands of Egyptian cotton sheets in the United States today and you probably won't find many of them that are available on Amazon. They tend to be expensive and can run into nearly $1,000 for a full set of sheets and pillow cases.
Fortunately, you can see a list of the best Egyptian cotton sheet brands that are around here: luxuryofthepharaohs.com . It contains a list of mostly high end Egyptian cotton sheets, but some blends are available for those who can't afford the higher end prices of the real thing.
One brand that comes to mind when talking about Egyptian cotton sheets is Sferra. You can buy these at high end department stores and they're sometimes available on Amazon.
Another brand that you can always rely on to produce high quality, durable sheets is AQ Textiles and these are available at Macy's for a few hundred dollars per set.
Last, but not least, Matouk is another brand that you can't go wrong with. But, again, these are expensive and go close to $1,000 for a full set of sheets plus pillow cases. If you want high quality, it's not going to come cheaply. The trade off is that you won't have to buy sheets for the next decade.