Combination cases to hold a flute and piccolo are fairly common.
You should have to worry to much about mixing brands for a case such as this.

There are also flute cases that have an exterior pocket large enough to hold a piccolo case.

Joe B

right you are Joe

I have a case where my piccolo zips into a pouch on the top of my flute case cover.

you can always just stick the picc in your back pocket

Just don't sit

ouch, I had a bad dream before a concert that that happened, but Joe B knows about the time I really did sit on a flute...

I'm having bad visions of squashed flutes, not to mention all those spiny little rods... ouch...

Lol!! Patrick, I hope you were okay after that, not to mention the flute!

My cousin sat on her flute once and it bent to banana shape. She managed to get it well repaired for a fairly low price luckily!!

I have a flute and piccolo case cover bag (like the flute case cover with piccolo pocket), which is great because not only can I fit my flute and piccolo in, but also all the accessories I ever need as well as my mobile phone, a small hairbrush and my keys! The strap is slightly broken but it's still good, and I don't know how I coped without it before!