Well I tweaked and tweaked and finished the pattern for a longways version.
These are very similar to the original pattern, but you increase before and after the markers.
I couldn't make up my mind whether to include the short rows or not, so I left notes to explain how to do them or not.
Short rows gather the mitten in at the wrist and fit nicely. Not working the short rows is easiest, but you get a bigger wrist. Both fit my wide-boned thick wrists, so try them both.
The finished mitten! Pattern on my sidebar.
Here is how the longways version looks after I bind off and get ready to start the thumb.
Here is how I close the gap when you place the last bound off stitch back on the left hand needle. I knit the thumb stitches, the last bound off stitch and then pick up a stitch from underneath this stitch and knit it together with the next st.
Here is how I add on extra stitches for a longer cuff without changing the stitch counts. I just place markers to differentiate between the extra stitches and the original stitches.
Any questions - holler!