Here's an interesting set of products for the dedicated roller skier: Roller ski boots from Alpina. I've only seen them advertised on the WebSkis.com website, but a local shops may carry them. I have not tried them, so what's below is the marketing hype. If you're in a warm area, or you want to save your winter boots for skiing, you may want to give these a try.
Alpina RRS Roller Skate Boots
A Titanium cuff on the skate boot offers lateral support for skating while allowing air to pass around the ankle. The carbon mid-sole assures the torsional stiffness of Alpina's winter skate boots.
Alpina RRC Roller Classic Boots
These summer-weight rollerski boots are low cut, light and the mesh tongue allows the breezes to blow on your ankles when skiing on those hot summer roads. These summer-weight rollerski boots (more like shoes, really) are low cut and light.
Both the skate and classic boots have NNN soles and a lace system the wraps the foot "...excellent roller ski to foot contact."
What makes them different is what they don’t have. They do not have an outside “spat” covering. This means ample ventilation while skiing in the hot summer months. They do have the Pebax outsole that is the same as that on the winter boots.
According to Alpina, the comments of many world cup athletes involved in testing basically stated that for roller skiing these are “the best”. Some even suggested the boots could be used on snow in those warm spring races.
And most importantly, "They are also on the peak of style."
Alpina RRS Roller Skate Boots | Alpina RRC Roller Classic Boots |