First, covers that DO fit the Plannerisms planners:
The Success Choice covers all fit the Plannerisms planner wonderfully (and their covers are delightful). The Success Choice covers come in a selection of beautiful leathers, with either an elastic or tab enclosure. Also now they have limited edition felt covers which look beautiful. I have one of the new felt covers on its way to me, expect my review next month!
Below you can see my Plannerisms planner in my leather Success Choice cover (which I reviewed here). It fits perfectly with a little room to spare.
large Moleskine notebook).
The Success Choice (www.thesuccesschoice.com) ships worldwide. You can see all of their covers here. Don't forget you can get 15% off your entire order at The Success Choice by entering the code plannerisms12 at checkout!
Some covers I haven't tried but seem like they should fit are the Franklin Covey Classic size covers for their wirebound (not ringbound!) planners. The Plannerisms pages are 5 1/2 by 8 1/2 inches, the same size as the Franklin Covey Classic size pages so it seems like the books should be the same size and the covers should fit. But since I don't have one myself I can't confirm for sure. **Updated: Please see Linda's comments below that the Plannerisms planner fits perfectly in the Franklin Covey Classic size covers for their wirebound planners!
Another option is a customized cover from Renaissance Art (www.renaissance-art.com). If you give them the dimensions of any book they can make a cover to fit it. They have loads of colors of leather to choose from, and you can choose from lots of styles with card pockets and pen loops.
I've also seen covers on Etsy and elsewhere designed to fit planners with the same page size as the Plannerisms planners (5 1/2 by 8 1/2 inches). If you send them the dimensions of the Plannerisms planner they will be able to tell you if the cover will fit.
The dimensions (as measured by me) of the Plannerisms planners are: height of the cover is 8 11/16 inches, width of the cover is 5 5/8 inches, total measurement of the cover from the edge of the back cover around the spine to the edge of the front cover using a measuring tape is 11 3/4 inches. With that information you can ask cover manufacturers directly and they should be able to tell you if their covers will fit the Plannerisms planner.
***Edited to add: another option without adding the weight and expense of a cover is to get a stick-on pen loop from Leuchtturm 1917, which sticks into any book (google to find your local supplier) and stick a Planner Pad Insta-Pocket into the front cover for cards. (You can see my post on how the Insta-Pocket works with the link to its product page here, no affiliation, it just worked for me).
Covers that DO NOT fit Plannerisms planners:
Covers designed to fit the large Moleskine planners and notebooks sadly do not fit the Plannerisms planners. This includes the Rickshaw Bagworks Moleskine folios, even the ones designed for the daily planners. Here's why:
The Plannerisms planner is a little wider and slightly taller than the large Moleskine.
The Rickshaw folios are designed to fit the back cover of the large Moleskine notebook:
Since the Plannerisms planner is wider, it overlaps inside the spine of the folio:
...preventing it from closing.
If the cover were designed to fit all the way around the book onto the front and back covers, it would make sense that a cover designed for a thicker book should fit the wider Plannerisms. But since the folio fits the back cover only, the Plannerisms is too wide.
I have a Renaissance Art leather cover specifically designed to fit the large Moleskine notebook snugly, and the Plannerisms planner cover is just slightly too tall to fit into it:
**Edited to add: I took some quick photos to show the Plannerisms planner with the Dodo Pad slipcover, which unfortunately is too big:
The Plannerisms planner is a full two inches narrower than the Dodo Pad original desk size diary:
Top view, you can see how the Plannerisms cover doesn't stay in the slipcover pockets very well and tends to slide out:
Another cover that does not fit is the Flex by Filofax. It is designed for A5 size books, which are slightly shorter and wider than the Plannerisms planner. For this reason the Plannerisms is too tall to fit. I don't have a Flex so I can't show photos, but this has been the report from Flex users.
I hope this helps!
Have you found other covers that do (or don't) fit the Plannerisms planners?