I actually use a regular clothes roller to house and roll around all my stuff -- my steno machine, laptop, some books, and all the cables. It's VERY handy, and no one can tell the difference. But even if they can, it doesn't matter. I like my handy-dandy clothes roller... A LOT! It's way cheaper than any "specialized" roller for a steno machine, and it still gets the work done!
i once made the mistake of using a generic office rolling suitcase that had no inside padding. Because of rolling on uneven ground, my machine suffered from vibration damage that cost me expensive maintenance service and parts replacement. So no matter what you're going to purchase, be sure it has adequate padding for your writer. Samsonite is the best, and I think Stenograph carriers are made from Samsonite. Check out Stenograph's web site for carriers. In my opinion, they offer the best.
I am not familiar with the Diamante writer. I am on the Mira. I got my case over a year ago when I got my new machine. I got it from Target, and it is a Swiss 24" "carry-on" case w/ a padded laptop sleeve built in! It has several zippered pockets inside to accommodate my power strip, cords, batteries, books, and anything else you may need! I absolutely LOVE it. When I purchased my Mira, it came with the standard Stenograph shoulder bag. I removed the velcro pads out of it and stuck it in my Swiss case, and it works great! This case holds everything for me, so now my hands are free of clutter! Okay. I am beginning to sound like a Swiss advocate....I gues I am!
I got my bag from Ross for $29.99. No need to buy one made esp. for your machine, that will cost wayyy too much. I do recommend getting the Jet Tote that stenograph sells to better protect your machine.
I have my Diamante in a Buxton Small Tote w/Wheels from Staples, $99. The organizer pocket from the Diamante soft case straps in perfectly on the interior back wall of the case and the machine slides neatly into a net pocket on the front side of the case. I love it. I can carry all my Stenocast wireless gear, extension cords, charger, microphones, tripod, and there's still an outer zipper pocket with some padding i can slide my small notebook computer (12in) into. I like it SOO much more than the Pirouette from Stenograph.