...is it normal to completely ice a cake with royal icing?

In the UK it is. Normally done on fruit cakes after it has a covering of marzipan.Yum!
Edited to say that is the traditional way but most people now use Sugarpaste (fondant) and use RI for detail work.

I tried it once on regular cake, and I wasn't pleased with the results....the icing was way to crunchy. It might be good on some types of cakes though.

As Rosiepan says, it's done in the UK. Nowadays it's all fondant cakes, but a lot of Christmas cakes are still made as fruit cakes covered in marzipan and then royal icing. The icing does go crunchy and some people like to use a spoon / spatula to tap all over the wet icing so it dries looking sort of spikey. The marzipan / RI combo is very sweet and not to everyone's taste!

Okay. I have a client that wanted royal blue icing...wasn't sure if he meant royal icing or the color royal blue. Heh. Thanks!

I would assume he wants the color. Otherwise he would have said "blue royal icing".

To use royal icing without it going hard, you add glycerine, the more you add the softer it stays, but this is only used for covering dont add it if you are piping with it.

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If he said royal blue icing, he wants regular icing that's royal blue. Most non-cakey people would have no idea what royal icing was, and almost certainly would ask for it to cover their cake.