I'm pretty sure a Cyclo Standard can handle that. Disraeli Gears says 26t, but
Standard Cyclo says 28t.
I got a Cyclo Benelux to shift to a 28t as well. It was a four speed derailleur that I used on a standard 14-28 freewheel. I was rarely able to get it into the 14t, but the others were fine.