I run a 26T large cog on 3 of my 4 road bikes, specifically because this is the largest size I can consistently run w/ almost any short cage rear derailleur. As Steve notes, 28T is a cram job, requiring precise chain length and wheel fore-aft positioning, w/ the Superb Pro, and this is true of most other short-cage derailleurs, as well.

I use a 42T small chainring because this is as small as I can go on a 144mm BCD, given that 41T rings are so extremely rare. A 42/26 will get me up a hill too steep for a 42/23 or 42/24.

I use the 50T outer chainring because an 8-tooth drop provides a near-ideal 1.5-step ratio system w/ a 2-tooth progression in back.

Bianchi: 50-42/14-16-18-20-23-26 for general purpose 1.5-step; 5 minutes to change to 50-47/14-16-18-20-23-26 for flat ride half-step

Mountain bike: 48-40-28/12-13-15-17-19-21-24-28. I can use a -24T granny, but I have to finesse the 24-40 upshift to avoid jamming the chain and front deralleur.

Peugeot commuter: 45-42/13-15-17-20-23-26. This is a slick half-step steup, if you don't mind the 93-inch top gear, which is OK, but I would not want to go any lower.

1960 Capo: 49-46/14-16-18-21-24-26. I squeezed in an ultra-6 freewheel to replace the original 14-22 Caimi 5-speed block. 46/26 is a bit tall for me, but minimum chainring size w/ steel cranks and the original 3-6 bolt Simplex adapter is 45T, and there is no way the original Campag. Gran Sport can handle more than 26T.

1959 Capo: 47-38/13-15-17-19-21-23. (Nervar proprietary 128mm BCD. Fortunately, it is easy to adapt 130mm BCD chainrings to fit.) Should be 47-39 or 46-38, and the 23 could easily be a 24.

As for the top gear, I find 96 gear inches (50/14 on the Bianchi, 46/13 on the 1959 Capo) to be perfectly adequate.