Here is a link to the processional canopies listed at susanmaria.com - a traditional sacristy supply store. They are also easy to make if you are short on budget. You simply need a large piece of white or gold cloth and four poles. Simply cut squares out of the four corners of the cloth and attach the poles to the canopy in some fashion. If you can obtain white or gold fringes for the edges of the canopy that might be nice too. If you aren’t looking for a full processional canopy (sometimes called a baldacchino) but rather, an umbrella shaped canopy carried by one person (usually when a ciborium or luna is being carried out of a procession) called an umbrellino then you may need to look harder. I cannot find one on the internet and they would seem to be much harder to make.
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