Because they can be so cheap, bamboo sheets aren't often called a "luxury" product. There are a few brands, however, that make a product so exceptional that we can talk about it here without any shame.
Cariloha makes some high end, amazing sets of bamboo sheets. You'll find that they get some fantastic reviews and at $179 for a queen size set, they're definitely above the quality of the bamboo sheets that you'll find at Walmart.
They're fully elastic all the way around, so your sheets are going to fit snugly to your mattress every single time. They're only 230 thread count, but that's within the range of other genuine high quality sheet sets. If you want a quality set that's going to last a long time and you just have to have bamboo sheets, go with these.
Soft Surroundings also makes great bamboo sheets that are available at a somewhat smaller price point than Cariloha. These will run around $130 to $150 for a queen size set.
Bamboo Dreams sets by Yala are available at Fine Linens and are a bit expensive at around $250 for a full set.
These are a few of the high end brands that are currently available. Even though there are others, the 3 we listed above are the best.